Runs, but no Idle

[bjl4776]

I recently got a '95 325is for a project that has been sitting for 4 years w/o running. It took my some convincing but i finally got it running, the only problem is that is has no idle at all. I have to keep my foot on the gas for it to keep running, but it runs strong at upper RPMs. I already cleaned the ICV and it moves as free as can be. Could there be a ristriction that is choking it out at low rpms or are the rings not fully set yet from the long hiatus, or am I on the completely wrong track?

Pics of the 325is

[SHOracer]

If the car does not idle at all, can you hold the rpm at about 800 with the gas pedal? Is it steady or wont stay running? This will tell you if the problem is with the way the car runs or with the idle circuit. Post back with results please.

[bjl4776]

No, it wont run that low, it starts feeling extemely bogged down below 1500 rpms, I can hold it at about 1000 but it is extremely rough

[SHOracer]

Well that makes it part of the engine or management. Could be fuel or ignition timing. I would check compression first to see if it was overreved. A light missed shift will allow the car to still almost act normal at higher rpms, but have problems down low. A few lightly bent valves are not uncommon on the 5-speeds, happens more then it should.

If you have great compression it can also be the plugs or the injectors gummed from sitting, but this usually will make it run better and better as things clean themselves over a few miles.

[Robstah]

Check your ICV, MAF, the boot right after the MAF and the 2 hoses going into it, and any intake that you may have on the car.

[bjl4776]

Well i know the compression was completely gone when I got it, I had to put gear oil in the cylinders to pre- lube the pistons, and I don't know if they are fully sealed to the cylinder walls or not yet, I know I am still getting oil blow by so i assume not. Is there any way that the valves can be checked on the car without removing the head? It isn't running like there is a vacuum leak because its not trying to rebound from dying at all, but I did check for vacuum leakes and it seams of is there are none, cleaned the ICV, MAF seems fine from stomp codes and power on the harness, and replaced the intake boot after the MAF already. Tomorrow im going to put another new set of plugs in, as well as injectors from my spare M50 and see if that gets it going. The DME is new as well as the rest of the fuel system is in proper order with correct pressure at the fuel rail.

[RacermeX]

Check the fuel filter.
Do you have new gas in the tank?

[bjl4776]

Yep, drained the gas, replaced the filter, and most of the lines, and had a pressure reading at 3.5bar at the fuel rail. If any part of the fuel system is the problem it would have to be gunked injectors, which ill be able to try tomorrow

[SHOracer]

The no compression is the key here. The otherstuff will make little difference until you take care of the basics. I had a m50 that sat for 4 years after an accident and it did not suffer any compression loss.

To check the valves without opening the head you can preform a leakdown test, real easy, just like a compression test. Bring the cylinder up on the compression stroke and check where the air leaks out. It shouldn't leak down but if it does you will hear it in the crankcase, intake or exhaust, or more.

[bjl4776]

I havent had a chance to test the compression again. I had no compression before the gear oil in the cylinders, and I was told that was normal for setting motors, i still need to do a compression test and a leak down test. If the compression test are good results should I even worry about leakdown, or should i do them both to cover all of my bases

[SHOracer]

If you have perfect compression you don't need to worry about leakdown generally. If the compression is not perfect it will help you find the source of the lost compression. I forgot one more possibility for the leakdown, bubbles out of the radiator coolant tank, ie blown headgasket style.