Starting problems, hot or cold, not coolant sensor

[dsmcrzy4life]

Hey guys this is his buddy. Im not very knowledgeable with efi. Theres no CEL light. It was suggested to change the engine coolant sensor, we did that, no resolve. Just to clarify, the sensor is the bottom one on the thermostat correct?

The car turns over fine, but fires hard. Sometimes it fires right up first try, usually not. So its intermittent. It'll stumble, sometimes die, sometimes clean up after it lights off. Once its started it runs fine except at idle. Today it was stalling after letting off the gas.

Any ideas?

 

[ilikespeeding]

Hows your compression looking?

 

[dsmcrzy4life]

Thats a good question. Dont know. The engine was torn apart recently for wrecked rod bearings. It got used pistons and rods put in it. Hone job and maybe new rings. (I hope). As far as I know the break in was done right. I have a tester, I'll give it a look tomorrow.

 

[dsmcrzy4life]

It does pull 20 vacuum though........

 

[ilikespeeding]

Im not worried so much that compression in itself is keeping your car down, but blow by will overload the PCV system on idle. When you get past 2k rpm, the crankcase will equal out pretty much.

 

[dsmcrzy4life]

We'll be changing the plugs and doing a compression check this weekend. What about the ISC and IAC? That seems to be a lot of people's issues with idle surging. Would it cause hard starting also? A boost leak test is in order also I guess.

Even if the cel light doesnt come on, could the computer still store a code? I have a couple obdII scanners but not I. Maybe advanced will scan it.....

 

[dsmcrzy4life]

Changed plugs and wires this weekend, the plugs looked good at the tip but were pretty black around the outside. I don't know when they were last changed. Got a cel, but havent gotten it downloaded yet. Advance auto doesnt have an obd 1 gauge. ??. Tried the key dance thing, didnt work.

It started up easy this weekend, but after about a minute of running, the rpms dropped and motor started surging, we drove it to Advance and it ran good except for a few misses here and there. Then at a stop sign, the car stalled after a couple seconds of idling.

 

[dsmcrzy4life]

Also, a couple weeks ago, I noticed the tps sensor wire wasnt on properly. It was just wedged in there. It didnt help anything, but I wonder if it was sporratically contacting and perhaps it went bad.

Just with guesses, I'm down the tps or iac. I'm about to try and disconnect each and see what happens.

 

[dsmcrzy4life]

Forgot to post that, its not good. 100psi, 140, 125, and 150. So we've got some blow by I suppose. Would the car throw a cel for pcv malfunction?

Im thinking disconnect the pcv line, leave the case side open and plug the TB side.

 

[dsmcrzy4life]

I noticed that the IAC is making a grinding solenoid noise. I disconnected it and the car ran the same (surging idle). When I start the car, it runs fine for about 4 seconds and surges. AFter I disconnected it and reconnected it a few times, the engine ran fine.

Tomorrow I'll test the pins to see if I get resistance within spec just so I dont waste 200 bucks.

Every since it has been much warmer out, the car has started very easily. When it was cold it would never start easily. I'm really thinking that its the IAC.

BTW, is there any way to fix or clean these? Since the solenoid is grinding, perhaps its stuck, which im sure is ###ed then.

 

[dsmcrzy4life]

The IAC tested out good. Today the car started hard. When it started, it surged bad. Shut it off and it wouldnt restart. A lot of gas fumes came out the exhaust. ALOT.

Its got a code, but the keydance didnt work. Too bad advance doesnt carry obd 1 gauges.

There's also a bit of oil coming out of the BOV. Does this mean the turbo is leaking?

 

[tunethis]

Try this. Homemade code reader.

http://vfaq.com/mods/wayback/BradBauer/electrical/code.html

(1g, T, AWD) Have your own ECU diagnostic tool for less than 2 dollars!!

 

[dsmcrzy4life]

Thanks man. Now the problem is getting the light to come back and stay on. It just flickers. Such a pain.

 

[dsmcrzy4life]

Well, I hooked up a fluke to the port terminals, and I got a constant voltage of 10-11 repeatedly, never going to zero. If I were to have had a buzzer or a light hooked up, I believe it would be constant. The check engine light was on.

The code page lists a constant pulse as ECM failure! Yikes! I dont quite have enough faith here to buy a new ECM.

What do you guys think I should do?

 

[dsmcrzy4life]

swapped out the ecm, car seems to run fine now.