Starting issue...

Arshad

Arshad

Legendary Member
Joined
14 August 2003
Messages
2,401
Location
Toronto, Canada
Some background first:

91 with about 95k kms. Also has an older style whipple 6lb CTSC. Walbro 255 fuel pump, with car running on the rich side.

Two days ago I went to go start the car and the engine would turn over and immediately stop. At the time I was running on fumes so I thought I was just not getting enough fuel. I tried this a few times with no go. I then tried starting and pressing down the throttle, but as soon as I got off the throttle, it died. I then turned it on again, held down the throttle for 5s or so and then it fired up normally. Immediately stopped at the gas station, filled up halfway and no problem starting. Stopped and started the car 2-3 more times that evening without any issues.

Next morning, same thing happened again (with half tank of gas). Needed the same procedure to startup. Went into work, tried starting it around 2pm, started up fine. Tried starting it again around 8pm and again no problem.

This morning, again would not start until I held the throttle down for several seconds.

Any idea on whats going on? It only seems to occur when the engine has been sitting cold for a lot of hours (but not sure why it started fine last night after sitting for at least 6 hours). After going through the above procedure of holding throttle down for several seconds, theres also a strong smell of fuel. Note that my car does run quite rich so maybe this is normal.

Is it a potential fuel delivery issue?

The only other thing that may have some bearing (although I doubt it) is that I normally use 94 octane but the past few fillups Ive put in 91.
 
It sounds like it's running too rich and you've fouled the plugs.. Try to start it without giving it any gas a few times. See if it starts after 3 - 5 items as it burns the gas that's in the chamber.
If it doesn't start, or even if it does, check your plugs. If they are fouled with fuel/carbon, replace them.

Good luck.
 
Arshad: I hate to say this, and I hope I am wrong. It could be possible that one of your cylinders have to much compression leak that the engine will not operate under idle. The car can run rich and not drown out because this is not a carb car.

The reason I'm saying this is because a friend of mine had the exact same issue, one day he went to his car and it won't start, when it did the car ran with the throttle down and dies out when he let go. The night before it was running fine. When they took it in, and did a compression test one cylinder was pretty much 100% leaking. The cylinder wall where the piston resides had changed to an oval shape. My guess is either the car ran without enough oil or cooling. If it is the cooling, then usually the top heads would give out first before the bottom block.

I hope it is a cheap fix like the spark plug or something. Good luck.
Peter
 
Peter, I really hope that's not the case! Since then I've started the car 2-3 times without any issue, even after sitting there for several hours. I've had the car sitting all weekend, so it'll be interesting to see what happens this morning when I start it up.

In your friends case, if he kept the throttle down for a few seconds, did it eventually start working, or would it not hold idle at all?
 
My friend's car would only turn once before shutting off (crank shaft / rpm). When he started the car and put at least 50% throttle the car would stay on at around 4k rpm but it was very lumpy. Once he released the throttle the engine would die out immediately.
 
Actually after reading your thread again, it could be that the engine is flooded with fuel and fouled the plug as slownsxt suggested. This is so common on the RX8.

The second test would be the compression test. You can actually check the compression while doing the spark plugs. Just look for the tool at any auto parts store.
 
Verify if the car will continue to run if you hold the ignition key at position III when you start the car and then shuts off right when the key is released (ign. position III back to position II).

If it does, it's would likely be the electrical portion of your ignition switch that is bad. Easy replacement.
 
An update:

Now it's behaving differently. When I started it with throttle and then let go, the engine RPM's fluctuated back and forth between 800 and about 2000 several time and then died. I did this a couple of times and then it held... seems to get better as it warms up. I'm going to take it into the dealership to see if they can diagnose the problem -- any thoughts in the meantime?
 
Could be a problem with losing fuel pressure on the rail. If the pressure bleeds off over time it would be hard to start. Once started and restarted after a short time the pressure would be maintained enough to restart.

I've seen this before.
 
Our car does this exact same thing, first it would not idle, then a couple weeks later it would start and the idle would wildly fluctuate....i really need to know what this problem is, also where is the best place to get an Auto tranny fixed and/or beefed up?
 
...when my main relay went bad the car kept trying to turn over but would not start...just click click...replaced the main relay and it fired right up!!
 
Drew: Based on the current symptoms (fluctuating RPM's), would you still say that the main relay is a possible culprit?

I think we can eliminate the electrical ignition possibility as well.

Losing pressure on the fuel rail certainly sounds like a possible root cause. Would the fuel pump be the culprit in this case? Note that I replaced the OEM fuel pump last year and put in a Walbro255 to ensure sufficient fuel supply to the CTSC (I had some indications that the car might be running lean). Since then the car has definitely been running rich.

BTW, I started the car up this morning with no issue. It looks like if I take it into the dealership I will have to leave it and have it sit there for a couple of days cold so they can try and duplicate the problem.
 
I believe it is time for you to check your Comptech RRFPR (Rising Rate Fuel Pressure Regulator):).

Check your fuel pressure, should idle about 43-46 psi, and go up from there through about 90 psi full boost.

I do not recall, do you have a fuel pressure gauge installed?

HTH,
LarryB
 
Larry Bastanza said:
I believe it is time for you to check your Comptech RRFPR (Rising Rate Fuel Pressure Regulator):).

Check your fuel pressure, should idle about 43-46 psi, and go up from there through about 90 psi full boost.

I do not recall, do you have a fuel pressure gauge installed?

HTH,
LarryB
Click to expand...

Thanks Larry, I was hoping you'd chime in :)

Is the RRFPR something that can potentially fail over time? ie have you seen/heard of this issue related to the RRFPR before? I don't have a fuel pressure gauge installed, so I'll have to get someone to look at it. If I recall correctly, the RRFPR is adjustable, right? Could it be as simple as an adjustment or you think it's the part itself that's acting wonky?
 
My car is NA but I had very similar issues, the car would die immediately after I started it. I thought it was the main relay but I replaced it and the problem continued. I replaced the ignition switch and it has been running and starting like a champ since. Its a fairly easy install, the part is cheap, and it fails quite a bit on our cars anyway so it wouldn't hurt to try!
 

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