psycko069

iTrader: (2)

So a little back story to hopefully answer any questions... Car has 62xxx miles on the clock. Moderate upgrades.. This is a relatively new issue that has arised, and the only change to the car since January is a new Shep 12 plate rear diff which should have no bearing on the issue I am having.. The car ran E85 from 2011 till October 2014 and there were very large fuel upgrades performed to go to ethanol, but no changes to go back. The reason I say this is that there may be corrosive issues maybe?? During this time the car was tracked exclusively (auto-x, time trial, HPDE, PDX).. Now its back to street/track time..

When the car is cold (all temp gauges read zero) the car has no issue starting. A new symptom I have noticed is that the fuel pump no longer primes when the key is switched to the "ON" position. It has always primes when the key was turned up until now.. Yesterday I checked the FP gauge when it was cold, and it read zero. I turned the car to on and it still read zero due to the fuel pump not priming. When the car is started, the FP gauge on the AFPR reads 40 psi at idle. Yesterday I was doing an oil change so I let the oil temp reach 140 degrees and shut the car off. It sat for about an hour while I was doing stuff. Afterwards I checked the FP gauge again and it still read 40 psi. This tells me that the fuel injectors are not leaking down, correct?

When the car is driven for an amount of time where it reached operating temps, and then shut off it will not restart. I noticed this a few weeks ago first. I started it when I was leaving work and let it idle for ten minutes to warm up. Drove across the street to get fuel, and it wouldn't restart. It took over five minutes of cycling to get it to kick over. It was raining....

The other day I took the car to run errands. It started right up when cold.. Went to get breakfast, and the car probably sat for an hour. I got back in to run errands and it started right up. From this point forward, every time I tried to start the car it wouldn't. It would take several minutes of cycling to get it to start. Again, it was raining..

I noticed that if I could get it to start and let it idle it would die.. If I pump the accelerator like an old carburated car and I could get it to kick over, if I held the RPM up for a few seconds then let it idle back down it would be alright and not die..

There are no other issues with the car. While its running it runs great. My sideband is reading as it always has. I have not tested anything yet... Ive read it could be the fuel pump, cam angle sensor, ECU water temp sensor among a hundred other things.. My situation seems odd because when its running its fine...

Mods that are pertinent to this
Walbro 400lph
AEM fuel rail
Aeromotive AFPR with gauge
FIC 1200cc injectors
fuel pump hardwire rewire
ECU is stock and retuned with ECU Flash on a dyno by a certified tuner

Sorry for the long post. I wanted to answer any questions before they were asked and define my issue as much as I could... Thanks in advance for all the help..

barneyb

When you write "cycling" what does that mean?

psycko069

iTrader: (2)

Cycling, meaning turning the vehicle on, attempting to start, then shutting it off because all the car did was turn over and did not start. Then repeat. There were a few times where it would kick over and attempt to run but would immediately die.

I pulled the car out of the garage last night. Hadn't run it in about 24 hours. It started right up. I don't understand it. This only seems to be an issue when the car is at operating temps.

MRolla

iTrader: (34)

Sound like you might have a failing fuel pump.

psycko069

iTrader: (2)

Thats what I was thinking, but wouldn't it have issues delivering fuel after the car started as well??? Not just when its trying to start?? Is there a way to test the output of the fuel pump??

barneyb

Stock ignition? If so maybe a bad coil.

psycko069

iTrader: (2)

Ignition is stock.. If it was a bad coil wouldn't it misfire while running as well??

barneyb

A coil is made of windings of very fine wire. If the wire breaks the coil is open. However, when the coil cools the broken ends can come in contact again. Anyway, the 4G63 runs not great with one dead cylinder. With two it probably won't start. It is easy enough to check, look for two cylinders with no spark when it acts up.

Another thing you might try is pulling the vacuum line off of the fuel pressure regulator when attempting start. You might possibly have a vapor lock problem.

The fuel pump advice is also good. The pump motor will sometimes get stuck, especially when warm. Once it starts running it will continue until the next time. Cranking while someone bangs on the gas tank will often start a stuck pump.

In conclusion: work through the easy stuff.

psycko069

iTrader: (2)

Yea I have one experience with dropping a cylinder. It happened at a Time Trials at Summit Point Raceway. After much brain scratching we found that one of the pigtail wires for the aftermarket injectors had broken inside the shrink tube.... It was a PITA to find.. The car isn't dropping a cylinder.. At least not to a point that I can notice it, so I imagine all cylinders are firing...

Vapor lock??? Hmm.. Might have to try that. What would cause vapor lock?? I never have been a fan of this pump.. It was installed to run ethanol but isn't an actual ethanol rated pump, so I have always had a concern about the pump becoming corroded... I might swap it regardless just in good conscience.. Just need to pull it to get the part number....

If I can get the problem to replicate today and have a second person around I might be able to try this as well as smack the fuel pump and see if either of these are the case.. Ill let you know..

boxerdropper

I wouldn't think twice about a fuel pump. Sounds like a case of vapor lock to me. Swap a pump walbro 450 are really cheap right now

psycko069

iTrader: (2)

The pump currently in there is a Walbro 400.....

boxerdropper

I understand you have a 400, just putting out there the 450 is cheap. With your afpr install and adjust base pressure should be quick easy install

kpr

iTrader: (6)

I just had a similar problem . Car ran great until it got hot then either wouldnt start or would shut-off while driving.

Mine was a bad omni power map. We had a very hot summer and my 4 year old Map just kinda fried and became sensitive to heat. If I let the car cool off, it went back to running perfect.

Also with the bad Map, car wouldnt prime the fuel pump.

migs647

iTrader: (19)

Curious why you were running an aftermarket map?

kpr

iTrader: (6)

For datalogging boost and SD setup. Cant do those with stock one