Bogging,misfiring,smoking!!!

[Timo1083]

Has new plugs,wires,timingbelt,headgasket.
OK to start i have a 90 laser rs turbo i rebuilt from the head up. I did everything according to the manual. My friend had taken it apart a year or so ago because it was running very bad and assumed it was the head gasket which it was not, cause i put it together and it still does the same thing.

anyways the problem basically it is running far too rich it smokes and cuts out at about 4200 or as soon as u punch it.and it misses throughout. the stock boost gauge spikes too.so i got a aftermarket one and it shows no boost!!. i can hear the turbo spooling.i can get it up to almost redline if i work the gas..

the idle air controller must be bad because it just twitches and makes noise all the time so i bought one off ebay and it did the same thing. so i tried blocking off the hole that the iac plugs. didn't change anything.

the ecu shows no codes just normal operation.

I replaced the mass air flow meter.did nothing still running to rich still bogging still cutting out and smoking bad. i got a compression tester and compresion is fine 154 across. the turbo has no play, and i have checked every sensor.

I also did a boost leak test and found a big leak in the intercooler outlet and fixed it. But this did not help, i re-tested and found that there is still air hissing in the head.

i also have adjusted the crank angle sensor with no luck. why am i getting so much fuel? would a bad IAC really cause all this? Would carbon gummed valves cause all this ?

 

[Timo1083]

i would also like to include that i bought a vacuum and boost gauge my vacuum is between 17 and 21. and in neutral i can take it up to redline with no boost. also sometimes i can not get above 4200rpm before it cuts out and this is only if, i very gradually raise the rpms. WOT boggs it out at any rpm. i can gradually raise rpm and get no boost up to read line but if i WOT i get about 2-3 boost at 2600rpms and it jsut keeps cuting and boging and smokin!!!!

also if i am idling and i WOT it goes to 2600 and stays. it spits and sputters and won;t go any higher. the only way to get my car past 2600 is to very gradually raise rpms. and even then it's almost impossible to get past 4200rpms


NO BOOST UP TO REDLINE!!!!!!ONLY BOOST WHEN WOT THEN CUTS AND SMOKES AND BOGGS RPMS WON"T GO UP!!!!

 

[ddavisaf]

You said you did a compression test. What were the numbers that you got for each cylinder?
You said you did a boost leak test. How long did you hold 20 psi for?

-Other things to check would be your timing. Make sure you havn't jumped a tooth or three.
-Pull your spark plugs and verify they're the proper ones... you need to run NGK BPR6ES gapped at .028".
-Ohm out your plug wires and make sure they're not bad.
-Check the resistance of your coil pack both primary and secondary coil pack.
-Try replacing the CAS with a know working one. Your CAS will control when your spark plugs fire. If it's not working you may be firing on the wrong cylinder.

If your ISC is bad if your car dies or idles irradically during any operation that requires the engine to work more. Such as turning on the AC, or pushing in the clutch, etc.

The hissing you experienced during your boost leak test is normal when testing at the turbo inlet. Try testing from the lower intercooler pipe instead. The reason being, during a static test from the turbo inlet air will escape past the rings and seals in the turbo, travel through your oil return line, into your oil pan, and up into your cylinder head. This completely normal. If you experience the hissing when testing from your LICP, try removing the pcv from the intake manifold and plugging the hole. If you are still experiencing the problem piston rings and valve seals are usually the culprit.

Let me know if you have any more questions. Post what you find so we can narrow this problem down.

 

[Timo1083]

Compression was 154 all across, i did the test from the licp because i know it bubbles otherwise. still hissing comming from inside the head. i know its not the pcv cause i blocked it off. 20 psi drops about 1 1/2 psi a sec, there are no other leaks!!

also i just got feed up with the iac and just unpluged it now i get smooth idle.

 

[ddavisaf]

If you're not holding 20 psi for 30 seconds or more there are more leaks.
Try spraying everything down with soapy water to pin point any external leaks in the system. Next run your boost leak test again but this time first rotate the crank 1/4 turn. Or you can set the vehicle to TDC first and rerun the test. Post your results.

 

[Timo1083]

If you're not holding 20 psi for 30 seconds or more there are more leaks.
Try spraying everything down with soapy water to pin point any external leaks in the system. Next run your boost leak test again but this time first rotate the crank 1/4 turn. Or you can set the vehicle to TDC first and rerun the test. Post your results.

I sprayed soapy water everywhere found no extra leaks. the boost leak is about 1 psi every 3 seconds. i can hear all the pressure escaping inside the head at a steady pace.
also set to TDC
NOW what???

 

[oldman]

Or you can set the vehicle to TDC first and rerun the test. Post your results.

Nope, TDC in any cylinder will result in valve overlap on the coresponding cylinder (1/4, 2/3) causing air to rush out of the exhaust pipe. 30* after any TDC would be a good place to be to ensure only one set of valves are open. Besides that, good job ddavisaf, I think I can finally retire from boost leak threads.

 

[ddavisaf]

Do you have a manual boost controller hooked up? If so that needs to be disconnected and the lines put back to stock.
How is the pcv disconnected?

Here's the thing. If you're leaking air into the cylinder head with the pcv disconnected you've got one of two things wrong.
Valve seals are bad, or your piston rings are bad.
If you're positive that your compression test is good and that your pcv isn't the issue then I recommend you run a leakdown test to find the exact location of the problem.

 

[ddavisaf]

Nope, TDC in any cylinder will result in valve overlap on the coresponding cylinder (1/4, 2/3) causing air to rush out of the exhaust pipe. 30* after any TDC would be a good place to be to ensure only one set of valves are open. Besides that, good job ddavisaf, I think I can finally retire from boost leak threads.

I meant go a 1/4 turn from TDC which should close the valves if I'm not mistaken. Sorry for the confusion. If it makes you feel any better *I* knew what I was talking about.

 

[Timo1083]

I meant go a 1/4 turn from TDC which should close the valves if I'm not mistaken. Sorry for the confusion. If it makes you feel any better *I* knew what I was talking about.

OK i did that and still hissing air so to pulled the valve cover off. i checked each cylinder at a time by pulling out one plug making sure the cams weren't opening the valve.then then i pressurize the system and still hissing no mater which one i test i can't hear the leak in any specific cylinder.i sprayed soapy water all over the cams and valves everywhere on the top of the head i could not locate any leaks yet there is a unmistakable hissing and that is where the boost is leaking I'm sure of it. i tried listening around the outside of the intake manifold but it is coming from inside the head. where is the air going I can't pinpoint it!!!!!