My motor keeps fouling plugs. It's a recent rebuild with 600 miles on the motor. We leaned out the PFC fuel map so the car isn't running rich, but it keeps fouling plugs. Just spent 30mins on the side of the road swapping them out for my extra set (keep them in the rear bins with a socket & ratchet...)

It's very strange. The car seems to be fine for awhile, runs smooth and nice. Then once in awhile out of nowhere the car just seems to die like its not getting fuel or spark. This happens when cruising between the 2000-3000rpm range. Once it starts to die, it will idle at 1100rpm without help but when i try to give it gas it cannot bring the rpm's up. Just giving it a little bit of constant throttle (in neutral) causes the rpm's to bounce between 1500-3000rpm. When it does this I change the plugs and that usually fixes it, but tonight, even after changing the plugs, it was still doing the same thing. I gave it a lot of gas and the rpm's shot up to 4000, then the car seemed to be OK. Was it getting flooded? Are my (stock) injectors going bad? Does the map need to be leaned out further?

I checked all the hoses - fine, oil - fine, coolant - fine, etc. The only that I can seem to identify is the plugs. Another thought was that maybe my map sensor is going bad...? Thoughts?

 

perhaps i need to run all 9's? i forgot to mention that the 7's were the fouled worse than the 9's when i pulled them. also, maybe i should invest in a HKS twin power?

 

You shouldn't need a HKS Amp just to run the car normally. It sounds like either your injectors are flooding the car or you have an issue with your ignition system. Did you have your injectors cleaned when you replaced the engine?

 

Exactly what I was thinking Kyle

 

no i didn't. the motor only had 29k miles on it when it died so we figured they were fine. it was just bad bearings, not a bad apex seals...that's why we figured the injectors should be were OK

 

Do you have a wideband or anything on the car which show your effects when you are leaning things out on the PFC?

 

we hooked up a wideband to tune the low end until the motor is broken in. leaned it out as far as we could without the motor running choppy.

 

So what exactly where you tuning for? It hard to know if you are just running too rich or if you have an ignition problem without knowing what A/F's you are seeing.

 

I had these problem a month ago, i had to deflood the car 3x in a month..
here's some help:
1. Most common is weak compression and plug fouling from sticking seals.
2. Too much fuel being added from larger capacity injectors (which can be adjusted).
as for my car, it was too much fuel, so i adjusted it at my dynotuning session. car runs fine now. hope that helps.

 

we were shooting for a balance between a goof A/F ratio and also smooth operation.

i believe the A/F range is between 12 & 14 almost all the time. keep in mind i have my rev limiter set to 4k, and also no boost controller or restrictor pill in the wastegate actuator line, so the car isn't making any boost right now. when we leaned it out so it was in the 13 - 15 range, the car wouldn't idle very well, and acceleration was kind of shaky.

 

Were you having this problem before you started tuning (i.e. on the base map)?

 

the PFC came with the "base mod" map. i installed the PFC when i installed the new rebuild, so there is no way to know. even though my car has the about the same mods listed under the base mod map list, it was running like **** straight out of the box. we leaned out the map from there and it was seeming to run nice, but once in awhile the plugs would foul. like i said, its mainly the 7's and not the 9's...

 

Unless you have non-stock injectors, I would use the base map first to get everything running right. If you are fouling plugs with the base map, then you really have a problem. Using the base map will at least take tuning out of the picture for possible problem areas.

 

I can say that i have had the same problems in the past and it happened to me just the other day. I was just cruising at around 2k and the car just went to die. And well it did. Turned it off and it seemed like it had flooded itself somehow. Just rebuilt the motor and stuff. I did not clean the injectors because they looked to be in good shape. But once again, i just had to bump the pedal to get it running fine and then it was ok from then on out. Could it be a similar problem with mine?