Fuel pump took long to prime...

[csmaan12]

Literally just happened, turned on the ignition and I heard the fuel pump prime for much longer than its usual time. Car started kind of weak (has been for a couple weeks) where it doesn't immediately go to its high RPM 2k cold start. It went from 1.3k initial and went up to the normal 2k RPM.

Starts right back up normally, but if I let it sit for a while it does that weak transitioning to normal start.

Could it be what from my injector/seal replacement? Or something else. I followed all the torque specs for the CS injector seals. I don't smell any fuel anywhere, been checking every day for the last 2 weeks since I installed them. Under the hood all seems completely normal.

Any ideas? There was another poster who mentioned weak battery, but why would that cause the fuel pump to prime so long?

[tastysi2004]

could be the battery. fuel pump needs that juice. if in doubt, take it all apart and redo it. check for scoring on the bucket, internals and double check each of the bolts. also check your pressure relief valve. if its bad, it may let off the extra pressure.
check the thread on how to tell if it's going bad.

[tegxsi]

Take a log while the pump is priming + cold startup. Include Voltage.

[csmaan12]

Originally Posted by tegxsi Take a log while the pump is priming + cold startup. Include Voltage.

Alright I'll do that and report back, interestingly enough it hasn't done that since I posted about it. Now just the slow start.

I'll post a log in a few hours when I get back from work, that way I'll have 2 cold start logs.

[csmaan12]

Here are three cold start data logs I took. I wasn't able to get the fuel pump to prime for a long time again, however I did get the slow start up you can see the RPMs start super low and build up to normal cold start RPM which is like 1800+.

[littleloogy]

Cold start:
KOEO-you should see pressure build to something close to 60PSI. If it does not get close to that on one key cycle, count how many key cycles it takes to get to around 60psi. You could have a check valve that is letting fuel bleed back into the tank.

If you get 60psi right off the bat and pressure does not want to build when you start, then I would think your mechanical fuel pump needs some servicing...

[csmaan12]

Originally Posted by littleloogy Cold start: KOEO-you should see pressure build to something close to 60PSI. If it does not get close to that on one key cycle, count how many key cycles it takes to get to around 60psi. You could have a check valve that is letting fuel bleed back into the tank. If you get 60psi right off the bat and pressure does not want to build when you start, then I would think your mechanical fuel pump needs some servicing...

Well pressure does build when I start, but I do notice that it's pretty much every time I start the car pressure is around 57PSI. When I start it, it builds up to 1700+ for the higher RPMs and settles down slowly to the idle pressure ~430PSI.

Only thing I notice, when it's not super cold out, lets say 40F+ there's this squeak that happens right when the fuel pressure goes from 1700+ and begins to come down with the RPMs as the engine warms up. To me that sounds like the relief valve. I'm not sure the spill valve would make that sort of noise, because it's literally happening only once, on cold start, and when there's a high > low pressure change. Does not happen while I'm driving at all even at WOT.

[littleloogy]

Cold start squeaky squeak

[csmaan12]

Originally Posted by littleloogy Cold start squeaky squeak

Yeah I read that before so I took it as normal. Just brought it up in relation to the low pressure on cold start. In any case would that answer why my cold start is so slow.


I'm not sure if you noticed RPM climbs from 1k to 1.2k, then shoots up to 1800+. It was never like that before. It would always go straight to 1800.

[littleloogy]

Originally Posted by csmaan12 Yeah I read that before so I took it as normal. Just brought it up in relation to the low pressure on cold start. In any case would that answer why my cold start is so slow. I'm not sure if you noticed RPM climbs from 1k to 1.2k, then shoots up to 1800+. It was never like that before. It would always go straight to 1800.

You running any E85?

[csmaan12]

Originally Posted by littleloogy You running any E85?

Yes, running an E30 flash tune from stratified.

I've had it a while now, no problems until just recently.

Also it took one cycle to get pressure above 60psi.

[littleloogy]

Oh, yeah. That would be the problem you must have some buildup of sticky goo. Clean your pump or put a bottle of a Redline Si-1 in your tank.

[csmaan12]

Originally Posted by littleloogy Oh, yeah. That would be the problem you must have some buildup of sticky goo. Clean your pump or put a bottle of a Redline Si-1 in your tank.

The whole thing or just the spill valve? Surprised how quickly it built up only on E30, not to mention internals are maybe a couple months old.

I'll give it a shot at cleaning and adding stuff in the gas tank.

Is the battery voltage looking normal in the logs?

[littleloogy]

Originally Posted by csmaan12 The whole thing or just the spill valve? Surprised how quickly it built up only on E30, not to mention internals are maybe a couple months old. I'll give it a shot at cleaning and adding stuff in the gas tank. Is the battery voltage looking normal in the logs?

I have not seen your logs, maybe I'll look tonight when I get home for work. What oil are you running? Certain oil work better with E85 then others.

[csmaan12]

Originally Posted by littleloogy I have not seen your logs, maybe I'll look tonight when I get home for work. What oil are you running? Certain oil work better with E85 then others.

I use Rotella T6 just like anyone else. Been using it since I got the car at 53k miles. Changing every 3500 miles, I wasn't getting smoking for the turbo during that time, but I used it as a preventative measure. Since it's common to the K04 on our cars.

[Wicked411]

I installed my autotech internals today. I go to get in car and it turns over but wont start. I went to get gas treatment. It started for 5 seconds then died. I've checked all my connections everything is good. I did it 2 times because the first time there was a ticking coming from a the plug by the turbo . Now I tried to wait for it to prime. But nothing seems to be working. Help?

[MSMS3]

Worked before the install. Not now. That equals an install error. Could be just about anything. Do you have logging or diagnostic equipment?

First check the electrical connection to the pump. Check actual voltage.
If good, check key in key off test for 60 psi pressure to the low side of the pump.
If good, remove the pump, disassemble, clean thoroughly with fresh gasoline, work in a very clean location, reassemble.
Follow the instructions carefully.