Engine does not work over 1/4 pedal and 12psi boost

[The Swede]

Hi all!

I have a rebuilt engine with TRW pistons, 208 cam, ported heads, MSD 50 inj, 70mm throttelhouse and body.

We have adjusted tps and iac correct and dubbelchecked the cam sensor.

Car runs great up to 1/4 pedal and 12 psi but then it starts to sounds like a popcornmachine.

I have always used AC-Delco R42TS in the car, have them gapped to .032, could the gap make this problem?

I also have the SMC alkykit and have tested with different times with it but no improvement....

Any one out there that can help me?

Thanks!

 

[Mac in SD]

Swede, it sounds like a coil pack or coil module to me.

 

[The Swede]

Originally posted by Mac in SD
Swede, it sounds like a coil pack or coil module to me.

Thanks Mac, we will change the coil pack later this week.

The coil module, is it the one on the passenger side closest to the passanger side?
How can we check if the module is gone?

Have a Stage II 1300+ coming up in a 25.1d chassie.....

 

[Mac in SD]

Uffe, the coil pack is attached to the coil module. I'm assuming you're using the stock-type 86-87 coil setup, right?

 

[smokinttype]

If what was just mentioned doesnt work, check the tps sensor. Make sure the voltage goes up STEADILY and doesnt RAMP up real quick. Just a thought.

 

[The Swede]

Originally posted by Mac in SD
Uffe, the coil pack is attached to the coil module. I'm assuming you're using the stock-type 86-87 coil setup, right?

Yes, from what i understand it's stock.

 

[The Swede]

Originally posted by smokinttype
If what was just mentioned doesnt work, check the tps sensor. Make sure the voltage goes up STEADILY and doesnt RAMP up real quick. Just a thought.

Thanks for the tip Matt, we will have a look at that also.

 

[OneLethal87GN]

Sounds to me like either the coil or module too. I would also pull the plugs to check their gaps. I've had plugs somehow lose the correct gap. The car would run fine until I got on it hard. It would then pop and backfire and stuff. I pulled them to find very different gaps. One plug even had its electrode melted off. I replaced the plugs and all was fine. If the plugs, coil, and module are fine then check the plug wires.

 

[VadersV6]

What are your O2's saying while you're getting in it? Are they very unstable and erratic? Turn your boost down and turn the alky off and see what happens. Get your 02's in the 800's and see if it still pops.
Hopefully someone didnt put your cam gear on wrong.
Any bad valvetrain noise?
Stick your head under the front of the car while its idling. Do you hear a tapping sound coming from your crank sensor, from it being adjusted wrong? I had a big popping problem under boost, and fixing my loose, wobbly crank sensor helped alot.
Any poor/corroded electrical connections to the injectors?
Ohm check your wires? Are any of them placed wrong?
This may sound like a stupid question, but is your gas cap seal in good shape? One time I left the cap at the gas station and couldnt figure out why my O2's went crazy and was running crappy.

 

[Lunkan]

The little I scanned the car this weekend, the O2´s where stable between 798-866

Uffe has to answer for the camgear, but it should be correctly installed.

No bad valvetrain sounds.

Crank sensor was ok, not loosened.

Some of the injector connectors are bad, but they´ve always been since he got the car. Lots of loose connectors just hanging, but we marked everyone in use.

Need to check them wires, and Uffe is going to get new plugs. But the plugs was doublechecked.

 

[smokinttype]

those 02's should be a little closer together...thats a broad range you got there, check the maf via computer, also check to see if the 02's are going rich lean rich lean and not sticking on just rich or lean.

 

[VadersV6]

Stick the tip of a little flathead screwdriver or an exacto blade, and bend or twist the female leads in the connectors for the injectors, so that when you put them on the injectors, they have a nice solid contact with the pins in the injectors. Check for corrosion.
What are these loose connectors? That doesnt sound good.

 

[The Swede]

Originally posted by Mac in SD
Swede, it sounds like a coil pack or coil module to me.

Thank you so much for that tip!

Have changed both coil pack and module now.....

Car runs like hell now!

Thanks again!

 

[Lunkan]

Thanks for the tips. Uffe drove the car over to me today and I had a look at it. Started with measuring the wire´s and they all where good. Checked the gaps and replaced 2 plugs that where wet. Also installed my old WG solenoid as former US owner hadn´t installed one (some sort of boost controller, like RJC´s). Also installed my coilpack and whent out for a testdrive. Damn it runs nice and spools quick

Took it back to my place and put back his coilpack and then a new testdrive. Started making popcorn again

Atleast we isolated the problem.

Thanks again guys.
/Andreas, Uffe´s private mechanic and PC support

 

[The Swede]

Originally posted by VadersV6
What are these loose connectors? That doesnt sound good.

Don't know but everything works on the car and no codes coming up.

I think Lunkan said something about some pics of them..... we will see later.....

 

[Lunkan]

Originally posted by VadersV6
What are these loose connectors? That doesnt sound good.

Here are pictures of them loose connectors, one of them was for the WG solenoid where I installed my old (got a new one), the rest I don´t know:
http://www.turbolunkan.com/temp/loose_1.jpg
http://www.turbolunkan.com/temp/loose_2.jpg
http://www.turbolunkan.com/temp/loose_3.jpg

 

[VadersV6]

Hard to make out. The 3rd one is normal. The first pic....is that the oil pressure sending unit?
The second one...I'm so disoriented, I cant really tell where i am. I know its on the pass. side by the master cyl, but cant really tell what else Im looking at. I dont have that blk/orange wire cut on mine, and dont think I have those 3 pin connectors around there.
I was confused by your post, as this usually means the car runs like crap: "Car runs like hell now! "

 

[The Swede]

VadersV6...... never mind about the loose connections.... the car runs like it never done before, no codes coming up and all is just fine!

I don't have the cruise control installed, could be one of the connections?

And i do have plenty of aftermarket gauges installed.

 

[The Swede]

Sadly this car is up for sale and i have 2 guys that is very interested of it.

Lunkan, me and another guy is going for the top with a StageII setup that you never have seen before!

 

[frankunderpsi]

wire conectors
1 oli sending unit

2 power master brake motor + pressure switch

3 power antena for radio