POPPING AT WOT, 16 LBS /PUMP GAS

[1badbuford]

I recently bought a 87 Turbo T, and after getting the car here, I took it for a spin around the block.
It pops at WOT with about 16 pounds of boost. I thought I knew what was wrong, I replaced the coil pack, module, <(from NOS 4GN) spark plugs (autolite 23's gapped at 33), wires, and put a known to be good stock MAF meter on the car. Would a bad MAP sensor cause it to do this? Or would bad gas cause this? I put about 8 gallons in the tank, it had about 1/4 tank of unknown age and condition gas in it when i got the car. Has anyone else ever been through this with bad gas? When I pulled the plugs it had autolite 25's in it and they were all fuel fouled, which would have indicated the parts that I changed. The fuel injectors have a green stripe at the top third of the injectors, and I believe they are 009's. The guy I bought it from says they are 50 pound bosch injectors and Red Armstrong chip. I am also considering changing the chip on the idea that maybe he thought they were 50's and are actually much smaller 009's thus it may have the wrong chip in it. The grounds looked to be good on the back of the heads when I pulled the coil and module. I guess I need to also get a fuel pressure gauge that i can see when its popping. I know with all the guys on here, someone should be able to help. Sorry for the long winded Post... thanks.

 

[trixdout]

Do you have a scanmaster installed? Get one and check for knock. Also get a powerlogger. Easy way to diagnose the car with those scan tools. White smoke out of exhaust? Coolant going low? Weird smells? Does it have a better fuel pump? Get a TT chip matched with injectors. That will get one headache out of the way. There should be numbers, written very finely on the injectors. That would indicate what type they are exactly. The chip take a picture and post it up. Take a picture of the injectors if the numbers are worn out or as an added help.

 

[TT/Ameasap]

Check fuel pressure with a hand held gauge. Should be around 40 psi with vacuum line off. Scan master numbers help a great deal in diagnosing on the Internet too.

 

[1badbuford]

Check fuel pressure with a hand held gauge. Should be around 40 psi with vacuum line off. Scan master numbers help a great deal in diagnosing on the Internet too.

Fuel pressure is 43 with hose off

 

[1badbuford]

Do you have a scanmaster installed? Get one and check for knock. Also get a powerlogger. Easy way to diagnose the car with those scan tools. White smoke out of exhaust? Coolant going low? Weird smells? Does it have a better fuel pump? Get a TT chip matched with injectors. That will get one headache out of the way. There should be numbers, written very finely on the injectors. That would indicate what type they are exactly. The chip take a picture and post it up. Take a picture of the injectors if the numbers are worn out or as an added help.

I have a scan master ., just got it haven't put it on yet... Not sure how long it takes

 

[TT/Ameasap]

Ported heads?

 

[1badbuford]

Ported heads?

Stock lb , ported heads came with car , but on the shelf

 

[TT/Ameasap]

Stock valve springs?
Check all hoses for leaks. Look for cracks in PS header. Tap on MAF at idle with a screw driver and listen to any idle change. While car is running, unplug cam sensor and see if it clears up.

That's about all I can think of at the moment.

 

[trixdout]

I have a scan master ., just got it haven't put it on yet... Not sure how long it takes

1 wire is ground. so any large metal place cloest to the scanmaster you can attach with a screw, 1 wire to the positive to a ignition port on the fusebox in the foot well and the other wire goes to the wire connected to the top second from the right port on the aldl connector underneath the radio. simple as that.

 

[1badbuford]

1 wire is ground. so any large metal place cloest to the scanmaster you can attach with a screw, 1 wire to the positive to a ignition port on the fusebox in the foot well and the other wire goes to the wire connected to the top second from the right port on the aldl connector underneath the radio. simple as that.

Sounds petty simple ... Try and get to it this week.. Keep you posted

 

[1badbuford]

Stock valve springs?
Check all hoses for leaks. Look for cracks in PS header. Tap on MAF at idle with a screw driver and listen to any idle change. While car is running, unplug cam sensor and see if it clears up.

That's about all I can think of at the moment.

No exh leaks .... Ill try the cam sensor

 

[1badbuford]

What about dirty crank sensor ?

 

[87chrisss]

Popping @ wot usually are signs of having a wiped cam lobe pop your valve cover's off and turn the car on see if you see any difference in rocker arm movement. You can also do a compression test/ leakdown test, its fairly easy.

I would 1st verify you have steady fuel pressure run the car with a gauge taped to you window, and verify your fp while driving and under boost. The next thing would be to check all your grounds very well, Install your scanmaster so you can see whats going on, It's always good to check your compression let me know how it goes.

 

[1badbuford]

Popping @ wot usually are signs of having a wiped cam lobe pop your valve cover's off and turn the car on see if you see any difference in rocker arm movement. You can also do a compression test/ leakdown test, its fairly easy.

I would 1st verify you have steady fuel pressure run the car with a gauge taped to you window, and verify your fp while driving and under boost. The next thing would be to check all your grounds very well, Install your scanmaster so you can see whats going on, It's always good to check your compression let me know how it goes.

I think it would have other signs if a cam lobe were wiped, it runs good until wot. I'm thinking fuel too, I'm not sure if the gauge I has will reach under the windshield wiper. May try after work ...

 

[87chrisss]

Do you have a compression tester?

 

[TurboBuRick]

It does sound like wiped out cam lobe but it could be the senor as well. Like mentioned, start the car unplug the cam sensor and go for a ride. If it still pops pull the valve covers and check valve lift. Look for a rocker not moving as much as others.

With a worn cam lobe the engine can run fine and show no sings of any problems until wot.

 

[1badbuford]

Do you have a compression tester?

Yep

 

[1badbuford]

It does sound like wiped out cam lobe but it could be the senor as well. Like mentioned, start the car unplug the cam sensor and go for a ride. If it still pops pull the valve covers and check valve lift. Look for a rocker not moving as much as others.

With a worn cam lobe the engine can run fine and show no sings of any problems until wot.

Oh ok, I was thinking it would make a little valve train noise... But you're right if it was over the nose wear it would be quiet ...

Anyone have a set of comp roller lifters for sale ?

 

[Mike Licht]

Look at the injector chip combo, looks like a problem to me

 

[1badbuford]

Look at the injector chip combo, looks like a problem to me

Hope so, I have about 5 that came with the car , I will take a pic of them and post it , hopefully someone can tell me which one if any will work with those green stripes ... Will also post pic of green stripes tonight ...