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swartz
07-22-2004, 08:23 PM
well the car just broke. was tuning it on a wideband came up to a stop sign and it started to stumble. wont rev past 1000rpms and if i press the gas down 5sec later there is a huge backfire. i got it home in 1st gear at 1000rpms. if u give it gas it basicly stalls. fuel pressure is normal and nothing seemed outa place according to the megasquirt. i took out the spark plugs and am going to do a comp test.

doesnt smoke or leak anything. coolant has no oil in it. but feels likes its in 5cly

is it possible to have blown a headgasket or rings with there being no smoke out the exhaust?

if it was a ring or head gasket when u gave it gas would it stumble and stall? thanks guys

MadmaX
07-22-2004, 08:33 PM
Even in 5 cylinder mode you should be able to rev.

You're getting gas(BANG!)
My money's on spark.

AdamF
07-22-2004, 08:36 PM
If the car falls on it's face when you open the throttle it's usually an AFM problem. The backfire is due to a lean condition.

MadmaX
07-22-2004, 08:45 PM
??????????????

What exactly is popping in a backfire if you're running lean?

I don't think his car has an AFM.

modifiede30
07-22-2004, 09:11 PM
How long have you been running with the megasquirt prior to the problem?

x628x
07-22-2004, 10:05 PM
yeah i think he said the other day that he has no AFM, so it must not be that.

swartz
07-22-2004, 10:40 PM
no afm. have had mega squirt for a few months. just any ideas on what would make my car run like crap and it wont rev. when i give it gas it wont rev and just stuble and pop and backfire wont rev past like 1500rpms. ill investigate more tommorow but if its not fixed then i cant go to nj on sun thanks guys

screaming_bmwe30
07-22-2004, 11:23 PM
replace your fuel filter, same thing happened to me.

swartz
07-23-2004, 12:37 AM
im gettin good fuel pressure though?

TriFlow
07-23-2004, 12:42 AM
im gettin good fuel pressure though?
Maybe you broke a rocker arm :( I hope not..

I'm on my 3rd set.. And I dont even have a turbo.

swartz
07-23-2004, 01:10 AM
what are the symtems of a broken rocker arm???

swartz
07-23-2004, 09:31 AM
bump jim any ideas?

bimmerjim®
07-23-2004, 09:39 AM
sounds like spark to me. youll BANG backfire when fuel is geting loaded up in the exhaust, youll pop pop pop backfire when its to lean.

your geting good tach signal, good coolant temp reading on the MS? this happened to me once, when the coolant tempo sensor pigtail cam unpluged. if the coolant temp sensor becomes disconected, it tells the ms that ist like -60f engine tempature, to the MS starts LOADING the engine with fuel.

check the plugs too.

whatever is happening is not just one part. like daniel said if one cylnder was not fireing, you could still rev it up fine, it would be rough, but you could still rev it up. im thinking its either the coolant temp sensor on the MS, or something spark related.

nateb
07-23-2004, 10:02 AM
I had a similar problem and it turned out to be my intake bellows had fallen off and was not properly connected to my afm any more. You don't have an afm but you still have some sort of intake bellows right?

The symptoms sound just like what happened to me.

Good luck
-nate-

swartz
07-23-2004, 10:05 AM
what does it mean if u take a plug out and smoke comes out the hole?? only happened on one of the plugs.

also the coolant temp is readin on the ms ill double check tonight. the plugs were not coverd in carbon they were dam clean. but i drove it back for 30m at 1mph. the wideband said i was lean as hell..and my a.f guage said lean as hell also.

if i have good fuel pressure could it still be a clogged fuel filter?

swartz
07-23-2004, 05:55 PM
bump

TriFlow
07-23-2004, 07:00 PM
what are the symtems of a broken rocker arm???

Loss of whatever cyl it broke on.. Probaly what sounds like backfires cant really remember but it's not pleasant..

Pop off your valve cover and see if there any shrapnel.. Rocker bits :shock:

modifiede30
07-23-2004, 08:44 PM
Does your car have a thermo-time sensor on the thermometer housing? If so, check it, I hear they'll cause lots of problems with injection if they go bad. It also sound similar to something that happened to a car I did an engine transplant on. We had a lot of problems with the timing. Have you done any work on the timing belt recently, or crank/tdc sensors? Check these sensors. If its picking up a bad signal, it might be throwing your timing off enough to cause problems but I'm not sure they'd be as severe as you're talking about.

bimmerjim®
07-23-2004, 11:19 PM
alrighht, i just tryed posting 3 messages 3 times. the first time it timed out, the second time it just went to a cannot display, and the third time it timed out.

so. short and sweet. if its not the temp sensor, then i can only guess its either the tach signal, or one of the wires to the injectors is messing up, and its only fireing one bank.

how long was the car sitting before you pulled the plug ans smoke came out of it? did the smoke smell like anything?

when you pulled the plugs, were they all white? or were half of them white?

swartz
07-24-2004, 12:10 AM
all white.....smoke didnt seem to smell like anything. i just did install an aftermarket tach like 3miles before this happened....but the ms tach is regeristering correctly...its been pouring here all day i didnt get a chance to look at it at all...i bought a new fuel filter though ill up date u all tommorw thanks for ur info and suggestions

bimmerjim®
07-24-2004, 04:40 AM
disconect the tach and see what happens, it may be robbing to much of the tach signal to feed the stock ecu, the MS the factory tach, and the aftermarket tach all at once.