334 code. Please help

[94stroked331]

Okay, now I am really confused. I came home from work today and put in the new EVR and ran all new vacuum lines (everywhere!). Now I am only showing 10 on the vacuum gauge. Reset the computer and went out for a little test drive and to get some gas. Maybe 2 miles car ran the same. Still surging at stedy speeds and still no change in RPMs when changing gears. I noticed that as long as the car was rollig above 5mph+/- with the clutch depressed the rpms stayed about 2000, under 5mph they deopped to normal. When I got home I pulled the codes and bam 121,136, and here we are again 334. There is a chance that the the EGR tube that runs between the headers and the EGR is nor seating a little. Where do I go from here?

 

[94stroked331]

Even more frustrated! I pulled all of the vacuum lines off that are attached to the intake and pluged ALL of them except 1 and that one I hooked the vacuum gauge to (no where to leak) and still only 10. Does this mean a valve train problem or an intake to head leak or something else. Please respond guys! This is killling me!!!!!!!

 

[HISSIN50]

The TPS code could be part of the surging.

FWIW, it's normal for the idle to hang higher than normal while your car is rolling. This keeps it from stalling while you use brakes, PS, etc. 2K is too high though. Once the vac leak is found and the idle lowered a bit, that might abate.

If you manually set the idle higher than commanded, it can cause some surging as the EEC tries to lower it down.

 

[94stroked331]

So after blocking off all vacuum ports from the intake and still only showing 10 on vac where else do I look for a leak? Is it internal maybe? Should I pull the upper and lower intake off and see if the gaskets between the lower and head have been compromised? Maybe they moved while installing the lower and are not sealing the ports like they should be. Thanks for responding by the way.

 

[2002BLGT]

first of all I dont know what the spec is but there is a spec on how far the actual throttle blade should be open , I wanna say its like .010 or something like that if you check it with a feeler gauge , basically close it till it sticks and then just turn it out to the point that it doesnt bind .....if you have it open too far this could be a cause for the low vacuum

did you say you set your TPS at .6 ? it should be in the .93-.99 range when the engine is running

your base timing set at 10 ? did you check to make sure the balancer had no slipped or replaced the balancer ?

fuel pressure should be at 39 with vacuum off and plugged

 

[hotcobra03]

high idle/timing

i have read about guys having problems with idle after bolt ons//something with intake sitting higher and it pulls on the throttle cable...if it were me i would double check firing order,turn down the idle screw till it doesnt hit and start car,adjust idle and set timing..than reset tps ,,,i would also do a compression test even though you put on new parts

 

[94stroked331]

So far this is what I have done. Replaced the EGR, EGR pos sensor, EVR, ALL new vacuum lines, cleaned the IAC. I am going to readjust the TPS to between .93 and .99. I am sure that this will not take care of my problem, so I am planning on pulling the upper and lower intake off this weekend to see if maybe the lower gaskets shifted when installing lower. If that is not it I am going to check valve geometry. I am going to recheck push rod lenght. There has to be a reason thet the enging is only making 10 hg vacuum and since I plugged all of the other vacuum ports coming off of the intake and checked the vacuum and it was the same it has to be internal, right? Anyway I will update as soon as I know something. Hopefully my troubles can help someone else.

 

[HISSIN50]

If you have a leakdown tester, I'd use it to see if you can locate the valvetrain or other issue.

 

[94stroked331]

I can't remember if I bought one or loaned it from Advance, but never the less I will do that first. I went to the parts store today at lunch and ordered new lower intake and lower to upper gaskets. The lower gaskets that my car calls for and the ones that AFR and Holley recommend are different. I put on the ones that are stock for a 94 gt. Maybe that is the problem. I ordered the ones that AFR and Holley recommend since I have AFR heads and a Holley Systemax II intake. Cross your fingers!

 

[94stroked331]

User name change.

 

[hotcobra03]

TESTERS?

If you have a leakdown tester, I'd use it to see if you can locate the valvetrain or other issue.

compression gage and leakdown tester are 2 different types of testers?When a compression test is being done,would a bad valve or say intake gasket, loose pressure if compression tester is left on? or do you really need a different tool and put engine at tdc ?

 

[HISSIN50]

compression gage and leakdown tester are 2 different types of testers?When a compression test is being done,would a bad valve or say intake gasket, loose pressure if compression tester is left on? or do you really need a different tool and put engine at tdc ?

They are two different types of testers. A leakdown tester is much more precise (an engine can pass a compression test, even a wet and dry batch of testing, and fail the leakdown). He probably passes a compression test easy.

For something as subtle as this will be, pressurizing each cylinder at TDC, with the engine off (so one can hear where air is going, and see the gauge drop) is going to be helpful.

 

[94stroked331]

Okay, I wll not have time this weekend to do a compression test I did however do a cylinder balance test. The first pass gave me cylinders 2 and 3. I immediatly ran it again for tighter tolerance and it gave me a 9 (pass). Why the different readings? I am having trouble locating an affordable leak down tester and no one loans them out. Should I just do a compression test? If I don't have a leak down tester can I just pressurize the cylinders one at a time and listen for leaks? Because of the lack of vacuum I think maybe an intake gasket or a valve not adjusted properly... What so you guys think? I am still getting code 334 even with new EGR, EGR position sensor, and EVR. I am stil also getting about 2 hg of vacuum at the EGR. Could this be because my engine vacuum is so low? (8hg at idle)

 

[94stroked331]

Okay. Last weekend I did a compression test all cylinders were between 145 and 155. Still only have about 8" of vac. This past weekend I pulled off the upper and lower intake. while in there I readjusted the valves just to make sure. Put everything back together with new gaskets and now I have 12" of vac. and a little better idle. The upper to lower gasket was wet near the back runners. Maybe from the starting fluid??? I do not have any codes (engine not running or running) but the vacuum is still a little low and it is still surging a little. Since doing the rebuild I haven'e had a chip cut (dyno tune) for it yet. Does anyone think this may solve my troubles?

 

[hotcobra03]

vacuum

now that you pulled it apart,lets start again...12 inches ...what is the needle doing? steady?jumpy?..its still a toss-up here

 

[94stroked331]

It is steady. At least as steady as the idle and that is a toss up. It seems to idle between 800 and 1200. The idle steadily goes up and down sometimes and sometimes it holds at 800. I haven't seen a pattern yet. And the throttle doesn't hang up as much when changing gears either. I will drive it a little more tonight. maybe the comp is still adjusting...

 

[94stroked331]

Okay let me explain. The vacuum only moves when the idle moves and it moves as stated earlier. The surging and hard starting when hot are the only problems that I am having and the valve train does seem a little noisy. It runs like a scalded dog though! VERY STRONG! I guess I just need to bite the bullet and either get a chip cut or buy a tweecer.

 

[hotcobra03]

exhaust temps?

your vacuum only went up alittle,,,what you did ,made a change in vacuum,but not in driveability...with your cats gutted its hard to say whats wrong cause the cats getting red was like a scanner for exhaust....maybe you can go and have temps checked on exhaust manifoilds with a lazer lite style tool... i have no idea what it should be but i know thier is a limit..i would do this soon...it cant be good if its that hot

 

[94stroked331]

I ordered a TwEECer today... I really have a lot of learning to do now!