Frustrating month

[mskrotzki]

Been a frustrating month -- and for more than just this damned virus: Had TB/WP et al replaced by Paul Z at Meatas in Peyton, CO (near Colorado Springs) at the end of May. Drove home with no incident – ran very, very well, although with traffic did not push it at all. Two weeks later I drove with a friend to Keansburg, CO and pushed it quite hard, and it severely overheated. Flat bedded it home and discovered the 27 year old radiator had taken a dump and the thermostat had stuck shut.

Ordered an aluminum Toyorad from SOHi Performance and a new thermostat from Tim Poliack and installed. Radiator leaked, spewing 2 gallons of Honda Type II all over the garage. Grrrrrrr. SOHi Performance sent a new radiator, I installed that, had some coolant left over and mostly filled system, drove it gently a mile or two and all was well – thermostat opened and temperature held steady. A week later I got the rest of the coolant, filled the system, lowered the car, got ready to take a full test and ----- it won’t start. The car’s rear end was raised about a foot off the ground that whole time for bleeding purposes, for whatever that information may be worth.

I can hear the fuel pump prime the fuel rail. The car readily cranks (new battery in December, and it lives on a trickle charger). It will fire once or even three or four times and then just crank. I’ve even held it in crank position to ensure the ignition switch is OK and get the same result. If I crack the test port on the fuel filter open immediately after trying to start it, gas comes out. I think that eliminates the dreaded Main Relay issue.

I have removed and double checked the ignition switch and the two separate connections required for position II are good. I’ve checked power to the TPS and MAP sensors. I clearly don’t have the diagnostic connector, so I can’t go further with the WSM trouble shooting steps. I’ve removed the controller box and checked all the vacuum lines and all are clear.

I’m wondering if anyone has a fuel pressure gauge to check fuel rail pressure while cranking to see if it sufficient. I’m leaning toward a fuel issue since it will fire a few times and then nothing – ignition seems ok. I’m chasing a fuel problem and hope it isn’t the fuel pump. I sounds like a miserable job and the car has ¾ of a tank of gas.

If anyone has additional ideas I thirst to hear them. Prime driving season in Colorado is short and it is disappearing rapidly.

Thanks.

 

[Old Guy]

I don't know the specific problem; but, the fact that your pump runs suggests that the main FI relay is OK. The fact that the pump goes through its prime sequence indicates that both the pump and the ECU is powering up which are the two relays in the main FI housing.

Based upon your brief description, as a first step I think you need to do a fuel pressure test as described in the service manual. Banjo adapters to fit the top of the fuel filter are available for a fairly low cost. With a non running engine you won't be able to do a complete fuel system test; but, following the procedure in the service manual will allow you to determine whether the pump is failing or the fuel pressure regulator has failed.

If the fuel system tests out OK, then things may be a little more complex.

 

[goldNSX]

pushed it quite hard, and it severely overheated.

That's very bad.
I see a higher correlation between that event and the non-starting issue than bad fuel delivery. Did you get white smoke out of the exhaust while severely overheating? It must be a pretty heavy burnt headgasket to not let start the engine but I'd search in that direction first.

 

[MotorMouth93]

I'll echo goldNSX and say you should take steps to confirm that the head gaskets are intact.

 

[mskrotzki]

That's very bad.
I see a higher correlation between that event and the non-starting issue than bad fuel delivery. Did you get white smoke out of the exhaust while severely overheating? It must be a pretty heavy burnt headgasket to not let start the engine but I'd search in that direction first.

I've driven it a mile or two while waiting to get additional coolant, and it started and ran fine during that time. It was only after getting the system full that it decided not to start. Surely there may be HG issues, but I won't know until I pull hard up to the continental divide that I can determine that. So far, I may have dodged that bullet, but we'll see.

I'm pleased that Old Man comes to the same analysis as I do. I'll wait a little bit and see if anyone in Denver has a pressure gauge I can borrow, if not I'll go buy one.

Thanks for your input.

 

[Big McLargeHuge]

SoS sells a fuel pressure gauge kit here https://www.scienceofspeed.com/inde...l-pressure-gauge-kit-100-psi-nsx-1991-05.html. You can get the gauge separate for $20 but you might just buy the kit for speed's sake so you don't have to hunt for the fittings and all that. Installing the gauge and replacing the filter at the same time might save you some time if it's never been replaced before. You can leave it installed on top of the filter for the future if you want.

You could try a liquid indicating leak detector for the head gasket if you're so inclined https://www.amazon.com/Lisle-75500-Combustion-Leak-Detector/dp/B0007ZDRUI. I think Kaz uses something similar for HG checks. It should only take a few minutes and might give you some peace of mind.

 

[goldNSX]

It was only after getting the system full that it decided not to start. Surely there may be HG issues, but I won't know until I pull hard up to the continental divide that I can determine that.

I'd do a coolant system pressure test, remove the spark plugs and would use an endoscope to see if there's coolant in the cylinders. While there a compression test can give more insights.
I don't think it's a fuel delivery problem (even though it to be the easier and less costly fix) but you might have a serious leak of coolant into one of the cylinders and it gets worse while sitting overnight or longer. Better rule that out first before damaging even more.

 

[Honcho]

I've driven it a mile or two while waiting to get additional coolant, and it started and ran fine during that time. It was only after getting the system full that it decided not to start. Surely there may be HG issues, but I won't know until I pull hard up to the continental divide that I can determine that. So far, I may have dodged that bullet, but we'll see.

I'm pleased that Old Man comes to the same analysis as I do. I'll wait a little bit and see if anyone in Denver has a pressure gauge I can borrow, if not I'll go buy one.

Thanks for your input.

Mark I'd check the fuel system first also. Your car has a lot of miles, so the pump could be tired. I know you have the RDX injector kit, so maybe check to make sure the injectors are fully seated and the harness plugs are not loose.

I'd also do a block gas test in the coolant bottle just to be sure. It's available at AutoZone and will tell you right away if you have a HG issue.
[MENTION=7151]mskrotzki[/MENTION] you can get one here too: https://www.amazon.com/Block-Tester-BT-500-Combustion-Leak/dp/B06VVBSFTF

 

[Old Guy]

I've driven it a mile or two while waiting to get additional coolant, and it started and ran fine during that time.

How much additional coolant? If you were low by a fair amount, then the temperature sensor may not have been providing you with an accurate measurement of the actual coolant temperature in critical areas of the head. If it was less than 1 l, then that might not be an issue.

You may have a head gasket issue which might have occurred after the first event and just evolved with the final restart attempts. I still think that you have some kind of fuel issue. Unless you blew both gaskets around every cylinder, I would expect that the engine should start. When i replaced the spark plugs on my 2003 pilot I received a phone call as I was just completing the job by starting to connect the plugs to the coils on the back cylinders (front side done). When I came back, I forgot that I hadn't actually plugged in the coils (you can't see the back side coils unless you are standing on a stool or step ladder). I test started the car and the engine fired right up and idled just fine on three cylinders and there was no CEL. Its only when I went to back up that it was apparent that something was amiss. As such, if you have 2 or 3 sort of good cylinders I would expect that you should be able to start the engine. Even if you have close to 0 compression on all 6 cylinders and the engine does not start I would still expect that you should be hearing the pffft noise you get when the plug fires if gas is entering the cylinder and you have spark.

You have to start the diagnosis somewhere. Whether that is with fuel pressure or a compression tester or coolant system pressure test will depend on which tools you have access to first. If it turns out that the problem is fuel, I would be inclined to follow up with a compression test and a cooling system pressure test or dye in the coolant to determine whether you have a lurking issue that is going to come back and bite you on some spirited drive.

One easy no-cost thing you can do is to pull the oil dipstick and examine the oil. If the oil shows signs of contamination with coolant don't bother attempting to restart the engine. At that point its a decision as to whether you do more diagnosis to confirm the problem or just proceed to engine removal. Absence of coolant in the oil is a good thing; but, not a guarantee that there is not an HG problem. The other no-cost thing you can do is to check the coolant level and see if it has dropped during your restart attempts. If it has that could be a bad sign.

Hope its not an HG issue.

 

[Old Guy]

I'd also do a block gas test in the coolant bottle just to be sure. It's available at AutoZone and will tell you right away if you have a HG issue.
@mskrotzki you can get one here too: https://www.amazon.com/Block-Tester-BT-500-Combustion-Leak/dp/B06VVBSFTF

If the gasket had a partial failure after the first event then the combustion gasses in the coolant test may pick that up - depending on how big the 'flush' was.. However, if the failure was later and the engine has been run very little or not at all subsequent to the failure I don't know whether there would be enough gasses in the coolant to get reliable detection. I don't know how sensitive the reagent is.

 

[goldNSX]

Another (not the most comforable) theory is that the pressure in the coolant system went high enough to let the old radiator explode. If the HG presses combustion air in the coolant system you'll definitly have a problem and this may occurred during the hard drive.

 

[Kaz-kzukNA1]

You can carry out the Eng Block test without driving hard for the initial inspection on the H.G.
You just keep the engine at idle rpm.
It's very sensitive and because of the design of OEM tank, you need to be careful not to contaminate the test fluid with the coolant and also block the overflow tube if your test setup allows the air entering through the tube.
I'll leave it for now as you can't even keep the engine running.

I'll presume that you double checked that all connectors inside the cabin, Eng bay, etc are fully locked.

If you have supercharger or any modifications that bypasses the fuel pump resistor, please ignore the rest of this post.
It won't be the cause of your issue.

Please confirm that it's safe to fire up the engine.
If you already have some damages, you don't want making it worse.

From what you wrote so far, please try this.
It may provide some idea.

Bypass the fuel pump resistor by creating short circuit loop like in the above photo.

Ideally, you should use proper 090 size terminal but probably you don't have access to it.
If that is the case, you can use paper clip to create the short circuit.

Again, ideally, if using the paper clip, best to insert it from the back (wire side) and not into the terminal opening but being as WPC spec, not easy and may create new issue in the future.
Therefore, if using the paper clip, please pay extra attention not to force or damage the terminal itself.


Please note that you are handling live IGP (about 14.5V) source at high current so never let the paper clip touch any part of the chassis or metal objects.


If you manage to fire up the engine using this method, I recommend keeping it to max 30sec as you have most likely trapped some air in the cooling system.


Kaz

 

[mskrotzki]

Well -- I'm afraid I'm hosed. I bypassed the resistor and there was no difference. It tried hard to fire, lots of action, but no go. I then opened the expansion tank and there was a release of pressure.

Tried it again, with the resistor in line. Same attempt at firing and also, disastrously, the same release of pressure from the expansion tank.

I expect this is going to be expensive.

Thanks for all the help and good wishes. To answer old mans question, adding about 3/4 of a gallon filled the cooling system.

 

[The King]

I've driven it a mile or two while waiting to get additional coolant, and it started and ran fine during that time. It was only after getting the system full that it decided not to start. Surely there may be HG issues, but I won't know until I pull hard up to the continental divide that I can determine that. So far, I may have dodged that bullet, but we'll see.

I'm pleased that Old Man comes to the same analysis as I do. I'll wait a little bit and see if anyone in Denver has a pressure gauge I can borrow, if not I'll go buy one.

Thanks for your input.

Has Old Guy changed his name??:uncomfortableness:

 

[Lude_2_NSX]

First of all, this is an older car. Things break, and that's part of cost of driving a legend.

That being said, preventative maintenance is key. This is a very reliable vehicle, but without preventative maintenance, you will have frustrating months like this. It's better to perform the fix on your own time than to need it after breaking down on a weekend road trip.

You were proactive in the TB/WP replacement, that's exactly the right path to go down.

The months are getting hotter, the T-Stat and radiator problems were probably due to the 30 year old factory parts. I just replaced my radiator and T-Stat 2 months ago for that exact reason. If you haven't replaced EVERY coolant hose, do it NOW. You will be frustrated again because one of the ~20 hoses may end up failing this summer. Just do it:

https://www.scienceofspeed.com/inde...omplete-coolant-hose-kit-left-hand-drive.html

Another item that will leave you stranded (especially as it gets hotter) is the main relay. Replace that as well now. Put your current one in the glove box. Maybe you'll help another NSX owner out one day with it.

While you're buying parts, replace the ignition switch as well. Cheap insurance, just do it. Spend some time looking into other common failures and proactively address them.

All of this advice is coming from someone who bought a "rescue" NSX with deferred maintenance. Now I hop in that car and put thousands of miles on it without issue. It's all about preventative.

Now to the matter at hand... Get a fuel pressure gauge and install it on the banjo bolt fitting on the fuel filter. It's cheaper than buying/renting a tool and it's permanently installed. I did it when I was troubleshooting a fuel problem and it's worth every penny.

Spray brake cleaner in the intake manifold and turn the engine over, if it fires then you likely have a fuel delivery problem. If not, it's time to look elsewhere and follow the direction of some of the earlier posts. Nobody likes to hear "compression test", but after an overheating condition it needs to be checked.

Don't let this month discourage your NSX ownership. Things happen on older cars and that's all part of the journey.

 

[goldNSX]

Well -- I'm afraid I'm hosed. I bypassed the resistor and there was no difference. It tried hard to fire, lots of action, but no go. I then opened the expansion tank and there was a release of pressure.

Tried it again, with the resistor in line. Same attempt at firing and also, disastrously, the same release of pressure from the expansion tank.

I expect this is going to be expensive.

Thanks for all the help and good wishes. To answer old mans question, adding about 3/4 of a gallon filled the cooling system.

Sorry to hear that. Engine out again, new HG...not the first horror story on prime.
Better not try to start the engine even a single time. You'll never know how much coolant enters the combustion cambers while the car sits. If it's just too much you have to deal with an even higher amount of $$$$.
Now, you have the explanation why it started after a short break but refused to do so overnight.
The chicken or egg question is what has led to the HG failure? As the car came from a TB job at the dealer, did they make a mistake? There was a similar 'story' years back here on prime. If they did a mistake, the coolant system built up pressure and let the old rad burst. Low coolant kills a HG pretty fast in the NSX. Your rad must have been very week as the system pressure is limited to 1.1 bar by the coolant cap. With a handy coolant pressure check you would have been able to detect the weak rad.
Anyway, high miles, over 20 years old and still the OEM coolant parts are not a good combo. Part of the disaster might have been avoidable but it doesn't really help now.
Let's hope no further damage has been resulting. The next key decision will be to decide which dealer should fix it.
BTW: let flush the new coolant out of the system completely as it got contaminated with combustion gases and might got acidic, not good for the alu lines.
Good luck!

 

[Old Guy]

If you are cranking the engine and the expansion tank is getting pressurized without the engine starting I agree with [MENTION=10201]goldNSX[/MENTION] that you should not make any further attempts to start the engine. Don't bother with the fuel pressure test. A compression test, leak down test, cooling system pressure test or test of the coolant for combustion by-products would be in order if you think you might want to do the work and want to confirm the diagnosis. If you are thinking about having a shop do the repair they will likely want to do the diagnosis to confirm the problem.

An unfortunate turn of circumstances.

 

[goldNSX]

Whatever shop you choose point out clearly what the problem is. Further tests should be done with the spark plugs out. A coolant pressure test might press enough coolant into the cumbustion chamber to... Because the very first thing they're going to try is to start the engine...just to confirm the owner is right (that it doesn't start).

 

[JohnWayne]

Interested to see the verdict. I am curious what the release of pressure from expansion tank is a sign of?

 

[NSXGB]

I would imagine the pressure is a result of a breach of the head gasket between a cylinder and water jacket.

 

[Old Guy]

Interested to see the verdict. I am curious what the release of pressure from expansion tank is a sign of?

I would expect that it is a sign of a significant breach of the head gasket(s) allowing the air in the cylinders that gets compressed by cranking of the engine to enter into the cooling system pressurizing it. Cylinder pressures during compression tests in the order of 200 psi are not uncommon so plenty of pressure to force air into the cooling system if you have a significant breach. The double potential damage is that after cranking which pressurizes the cooling system, retained pressure in the cooling system can force coolant back into the cylinder. In a worst case scenario enough coolant might enter into the cylinder to create a hydro-lock scenario, hence my previous comment about no more start attempts. The fact that the OP released pressure in the expansion tank is probably a good thing.

I have often pondered that all aluminum engines need some big ass flashing warning light triggered by a rapid rise in temperature or a drop in coolant level in the expansion tank (hard to do reliably). I generally spend most of my time watching traffic and where I am going and only occasionally checking the dash temperature gauge. A hose / rad failure at the front of the car would normally be quite obvious; but a breach at the back of the car may not be immediately obvious. With all aluminum engines the time span between the initial event and subsequent major damage is very short.

 

[goldNSX]

Modern engines have a sender unit for a low coolant level. The NSX should have one too, so we should call it a engineering flaw. After market coolant bottle don't have a sensor either. Too many HG died due to not having that specific sensor IMO.

 

[Old Guy]

Modern engines have a sender unit for a low coolant level. The NSX should have one too, so we should call it a engineering flaw. After market coolant bottle don't have a sensor either. Too many HG died due to not having that specific sensor IMO.

Not exactly the most modern; but, my 2003 pilot does not have a level sender. Can you list some vehicles that do? Might be an interesting winter project to see if you could adapt one to the NSX using one of the aftermarket tanks.

 

[goldNSX]

Not exactly the most modern; but, my 2003 pilot does not have a level sender. Can you list some vehicles that do? Might be an interesting winter project to see if you could adapt one to the NSX using one of the aftermarket tanks.

You're right. VW/Audi used to have two separate sensors for the coolant and the oil level.

 

[mskrotzki]

Tomorrow will be an interesting day. The TB/WP was done by a top flight independent mechanic near Colorado Springs. He worked a long time for the Colorado Springs Acura dealer and was well known as one of two mechanics in the entire mountain states region who really knows the NSX. This was not a hack job by some kid on the corner garage. (Are there any more corner garages?)

My NSX is a high mileage (222,000+) 27 year old car. I've had it over 100,000 miles. It has always had an easy life -- I have knowledge of 2 or the three previous owners. My usage is generally long distance road trips. (see my tag line.) I has not been a daily driver as I don't daily drive, living in the heart of Denver, less than 3/4 miles from the capitol. It's been on the track a few times with no issue whatsoever. Still it is a high mileage 27 year old car. Who knows if parts of the cooling system were just on the ragged edge? Or if some oversight occurred during the TB/WP operation.

So, tomorrow I'll talk further with my mechanic and see what we do. I have faith in this fellow and there is little other choice. I'm going to keep the car as it is worth enough to put additional money into it. Wish us luck and I'll keep everyone posted. Thanks for all the interest and good wishes.

Mark