car missing/ hard starting-new engine

[stb94tsi]

I own a 94tsi and just had a rebuilt 4g63 6-bolt put in.my problem seems to be when I'm driving my car it seems to miss when accelerating (low or high RPM) almost all the Time I just changed the sparkplug wires thinking it might be miss-fire, but it still continues, then I changed the fuel filter but nothing different. Also when I'm done driving my car I shut it off and if it sits for more then 10 min I have a really hard time starting it, I have to press the gas really fast to get it to stay running and it takes about 20 sec for it to start running fine again.I don't know if both of these problems are related or not. So if any one has any ideas on whats going on, that would be great, also I'm thinking it might be something like my ISC, or my coil-pack, or maybe my MAF. Any kind of testing tips would work also....thanks

 

[femmeDSM]

Check your ECT (coolant temp sensor). When these go bad, they will cause hard starts that mimic fuel pressure related problems. Since the ECT is the first sensor that the ECU looks at when starting the car, when it goes bad, the ECU gets seriously confused and can do all sorts of crazy things.

I wouldn't suspect the ISC unless you are having idle issues - does your car stall at idle? Idle surge?

Are you getting a CEL?

 

[Old Mitsu Tech]

Right, most people overlook the coolant temp sensor.

Another thing you might do is have a snap kv reading done on your ignition system. This will tell you what the max your system can put out. If you have weak component, your ignition will work ok under normal circumstances. However, when demand rises as it does during accelleration it can't provide enough spark. This can lead to misfire.

Other things can contribute such as lean fuel, and such, but I'd do the scope first. This will reveal any shortcomings you may have.

Good Luck

 

[ddavisaf]

What about bad gas Claire?

Sounds like a coolant sensor to me. Also, check for boost leaks while you're at it.

 

[femmeDSM]

What about bad gas Claire?

Yeah, that too!
P.S. hey, congrats on the "wiseman" status there, 'Sparky'!

 

[ddavisaf]

Thanks

 

[stb94tsi]

thanks, where can i get a snap kv reading done at?Also I had a 95 ported manifold put on and their is a leak by the gasket, on guy a so called mechanic said i needed to get it milled down to fix the leak.....could that be another cause for the missing?

 

[Old Mitsu Tech]

Yes it can. it's called a lean condition. In my previous post I covered that. Get that fixed first before you do anything.

Scope can only be done at a shop that specializes in driveability/emissions repairs.

Lube Masters probably doesn't have one.

And yes, congratulations Damien. You deserve it. We're still looking for more

 

[stb94tsi]

hey thanks for the info, but the lean is happing from my exhaust leak right, if so do i have to get it milled?

 

[bumpinlazer]

you figure it out yet? i am having the same problem

 

[Turboeagletalon]

i was haveing this problem with my 95 6 bolt swop. i figured out that the injector plug for my number 1 cylinder wasn't makeing good contacked.

Start the car, Try removeing you your injector connectors one at a time. if you remove one and the motors rpm's don't fall, or the motor doesn't studder. that one isn't fireing.

Also your timing could be off. Remember to ground out the timing clip on the fire wall. And set base timing to -5 degrees. With the clip unpluged, it should be ideling at aboug -8 degrees