Car starts - runs fine for 10 seconds - then runs like SHIT!

[RyanZ06]

Here is the situation.

I have a M52 converted to OBD1. 413 red label, walbro 255lph fuel pump, other wise stock.

I am using a tree house adapter.

If i reset the ecu (leave the battery disconnected for a bit) the car will start, and run like normal for about 10-20 seconds, and then it just hits a wall. The car instantly starts dropping cylinders, and eventually dies, and will not restart (fouling the plugs).

I have no access to a code reader locally (i've been searching for one)... but I have treid to do as much diagnostic as possible...I cannot figure it out!

Does anyone have any ideas?

[FredK]

Crap, sounds frustrating!

What have you done in terms of diagnostics?

[RyanZ06]

Crap, sounds frustrating!

What have you done in terms of diagnostics?

Checked grounds, replaced o2, replaced coolant temp sensor, changed plugs, changed fuel filter...

the car has a brand new Cam/Crank angle sensor, brand new knock sensors, a new vanos unit, new water temp sensor...

The only thing left to try is a MAF sensor, and a IAT sensor.

[trent]

you don't need a code, reader, do the pedal trick and tell us the codes


I have seen ECU's do simliar

TTT

[e30polak]

check ur hfm...maybe fuel pressure regulator? coil packs...

[Bmjpv]

basics

Consider too much fuel? too much pressure because of a bad pressure regulator, Water temp sensor correct type or tunning too rich after cold starting?? Replace main fuel pump with OE to go back to basics. joe

[PiercedE30]

sounds like its air flow related. i've seen a few cars at the shop that ran like shit until we plugged a different hfm in.

[matt]

Definitely sounds MAF.

I swapped MAFs to a good one tonight (old one was sucky), and the car did exactly this. Then I reset the ECU and it was all good.

[Van Westervelt]

you don't need a code, reader, do the pedal trick and tell us the codes


I have seen ECU's do simliar

TTT

What is this pedal trick? I have heard of it two times now. And how do you get the codes that way? I have a reader, but I am curious about this too.

[mazur]

Just unluggin the HFM should help the car run better. It might be a little worse the first time you try to run it this way, but should run pretty well soon after....that is, if your HFM is currently crappy.

[RyanZ06]

I'll replace the plugs again tonight (they are fouled out again).. and try running it again without the MAF.

I wont swap back to the stock pump, because the stock pump is garbage, and it broke.

I will check the FPR, but how does such a simple mechanical device go bad? That doesnt explain the perfect start up , and then eventually/progressively dropping cylinders.

[trent]

What is this pedal trick? I have heard of it two times now. And how do you get the codes that way? I have a reader, but I am curious about this too.

search!

TTT

[RyanZ06]

no more guesses?

[Bmjpv]

guesses

not just gresses but educated guesses! What is fuel pressure? temp sensor (not sender)values and correct? Air mass meter do go bad but generaly don't go to full rich and flood out plugs. Don't look for the one in a million problem, it's all in the basics, don't loose that approch . joe

[aeryk7]

Sometimes a leaky valve cover will be the culprit of this, oil will get into the spark plug tunnels and when the car gets hot it will make the car misfire.