sputtering rally car

[A1337STI]

So I've been trying to track down a sputtering issue for over a year now.

It does it mostly when its cold out, and the car is cold, but on occasion it happens after hours of operation in warm weather. it seems to dump in too much gas.

I was expecting the issue to go away when i swapped motors but it did not, so I had the fuel pump & Filter changed but the problem is still here. Tom checked the voltage at the relay and pump . I changed the MAF two nights ago .

When i went through 80 yards of water at the rally my car was sputtering really bad for about the next stage mile and then it went back to normal operation. Anyone have ideas on what to check next? Tom wants to try swapping ECUs (which i'm game for) I'm wondering if it could be wiring to some sensor ?

what would make the car think it needs to dump in way too much gas?

[A1337STI]

Oh also btw i just had C&C clean the injectors , but it didn't change anything. when it does the problem i can get it to stop bouncing the car around if i pull back to about 20% Throttle, also if push the clutch down and Hold the gas it will continue to sputter but climb rpms , once above about 4500 it runs right and if i slip/murder the clutch i can drive forward and if i manage to stay above 4500 it drives normal.

[ScottyS]

When you swapped motors, did you also swap all of the intake manifold stuff - e.g. throttle body, etc? How about all of the sensors, are they new, or at least different?

If so, I would start with sensor wiring. Check connectors on the engine bay side, you may have to disassemble, restrip, and resolder some of them. Hopefully it's not an issue deep in the harness.....

Nothing wrong with trying a different ECU, shouldn't cost anything to try.

[A1337STI]

ya the new to me motor had an entire throttle body assembly that we used. all of the sensors came on the new to me motor (crank, cam, coolant throttle position)

eeeks ya sounds like i need to go into wiring / ecu now

does a GC have a seperate MAP sensor in addition to a MAF ?

[ScottyS]

Also, check the connector on the MAF itself.

[A1337STI]

Connector to MAF is fine. car was sputtering really bad today this morning, and again @ lunch, and i could smell gas from with in the car. I have a break in my exhaust 4" from where the exhaust manifold, just before my CAT so it could be gas in the exhaust stream, and i had someone 2 weeks ago tell me they could smell gas out of my exhaust.

also it looked like i got HORRIBLE gas mileage on my drive into work today
i got 29 mpg on my last tank, and looked on pace to get the same, but my car sucked down a Lot of gas on my way in (or i'm leaking) .. i have a 1/4" lexan shield under my gas tank, but i guess a puncture / tear is always possible.
fuel pressure regulator ?
?
I'll try and grab a spare ECU this weekend, anyone else have one handy? (for a ODB1 1.8L )

guess i should check my plugs? do they go dark/ black if i'm running rich?

[Kevin M]

Sounds like you might have a stuck injector. That, or you have no spark to one cylinder.

[A1337STI]

oh sorry
just before Desert Storm Rally
-----------
New to me motor (came with sensors, throttle body and throttle position sensor)
New Fuel pump
new fuel filter
new spark plugs
Fuel injectors cleaned up and matched at C&C !
cleaned air filter
cleaned MAF with MAF cleaner
Replaced MAF with spare from Ansel's car (Thanks!)

sputtering continues ...

[Kevin M]

I knew all that. But that's what the symptoms point to.

[A1337STI]

when its sputtering it doesn't feel like its running rough

Also my CEL comes on the entire drive up spooner, but goes off soon as i reach the summit and start headed down hill. the ODB1 1.8L has no knock sensor so It's not that, but maybe is a misfire? it did this on the old motor too... (May be completely unrelated, might be the same issue)

I Did hack off the silencer prior to the breather box, but its the stock breather box , and about 4" of the tubing coming out of the breather box .. hmmf

alrighty ... hmmf.

[Dean]

over pressure in the fuel system?
FP regulator?
Problem with the return line?

[van]

Your 17yr old fuel lines may be failing? A fuel pump change put extra stress on these lines that have long since lost their elasticity. I'm dealing with a fuel leak now myself due to these same circumstances,minus the sputtering stuff.

[A1337STI]

i've heard FP Regulator from an other buddy too...
http://www.napaonline.com/Search/Det...+50068+2068006
(89521 , click the first shop online)

$124 Bargain if it fixes my problem.. waste of cash if not ..

hmm well my lines are in the cabin how obvious is a line leak going to be? spraying, dripping out? or something that's harder to detect?

I don't know where the FP Regulator is .. but i'm fairly sure i'm on the original one ..

[van]

Originally Posted by A1337STI

hmm well my lines are in the cabin how obvious is a line leak going to be? spraying, dripping out? or something that's harder to detect?

Not in the cabin, on top of the fuel tank going under the backseats before they go inside. Look under the backseat passenger side under the cover plate. The lines don't have much room to move so when you pull the fuel pump assembly out it stretches out the old lines. I think all the lines forward are solid.

[A1337STI]

ooooh, Gotcha ! shouldn't be too hard to check, as the car is fully gutted. so even the trunk is now part of the cabin... hehehe

[Dean]

You Rally, so it is entirely possible a hard line is dented/crimped, or a rubber line fouled on the pressure or return side.

A failing regulator could also cause all sort of weirdness. You don't have to swap it, just put a F gauge on it and see what is going on.

[A1337STI]

anyone have a Fuel pressure Gauge?

I know Ansel/Dean put one on before i changed the motor / fuel pump and they said they saw it dropping when sputtering. but i never moved past that.. (not sure where they put the gauge either) i think they put it After the fuel filter (is that before the Pressure Regulator? )

I need to start a more acurate log book of all the maintainence that i've done and issues i've had... doh

[ScottyS]

Originally Posted by A1337STI

I know Ansel/Dean put one on before i changed the motor / fuel pump and they said they saw it dropping when sputtering.

Ah.

The FPR is at the end of the line....

[A1337STI]

So Tom pointed out the "new to me" motor came with its own FP Regulator that we are using now

I swapped ECUs last night. I still have the same issue, it was sputtering a lil bit this morning. the problem was not nearly as pronounced (but it was a lot warmer out too)

Anyone got an idea? I'll be coming down Saturday to do some more work on the car , we are changing out springs, bleeding the brakes, and replacing a track arm in the rear. Bent one really bad looks like due to an impact directly on the track arm.

My CEL going up spooner didn't happen last night (Tom did weld the exhaust to the exhaust manifold as it was leaking there) car feels a lil bit stronger in 4th going up hill. Gas mileage may have ticked up a lil bit as well too (can't really tell yet)

Damn sputtering issue WTF!

[Dean]

Did you put a FP gauge on it?

It is either fuel, air or spark...

Coil or coil packs?

Vacuum leak.

[A1337STI]

So Tom and I were working on the Rally car this weekend (which involved tom fixing things and me injuring myself with power tools .. angle grinders can really hurt )

We discovered my O2 sensor is broken, like way broken , little porcelain pieces falling out and what not. I disconnected the O2 wire Sunday on my way to napa and no sputtering. put in the new O2 sensor and so far so good. I won't really consider it fixed until i've driven the car about 5 days. (the problem was intermittent )

could this explain the gas smell i was getting on occasion. (makes some sense right?)
as all of the spark plugs indicated the motor was running rich.

car seems to be running a bit better (need less throttle to climb hills than before) won't really know until i can check gas mileage again, i was getting 30 (29.5) right after the motor swap

[Dean]

Hope that was it.

It had/has to be something you moved from one engine to the other.