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  #1  
Old 22nd December 2012
JasenMorrow JasenMorrow is offline
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Default Wont rev in gear.

Ok so as the title says my 1990 turbo wont rev in gear. It will rev fine in park/neutral. Had an issue with no boost but got that resolved. Now the issue is that when in Reverse or D or any gear it will only rev up to 2000 RPM. Thought it was the fuel pump so I checked it and it was making a weird grinding noise so I put the original back in and it sounds like its running fine. I can rev to 2000 RPM or so in gear and if I do this with my foot on the brake and the parking brake on it will build up to 5 PSI of boost fairly quickly. Checked for vacuum leaks and such and could find none. Valve timing is dead on and ignition timing is set at 20 degrees BTDC with the vacuum advance mod done and gonna be running 15 pound of boost with a 2.8 bar pressure regulator and SD fuel chip. Also when I put the car in gear most of the time the revs will drop and die almost instantly. Only started doing this after I fixed my vacuum leaks. Idles a little high at 1000 but I had dialed it down to 850 thats normal and it still does the same thing. AIC was just cleaned and slightly oiled with WD-40. TPS adjusted properly so that it clicks when throttle is lightly pressed. Although I haven't checked to make sure it is working properly. So my question is what could the issue be? I have no way to check fuel pressure right now. And I want to get the issue of it dieing when put in gear fixed before anything.
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Old 23rd December 2012
16saabs 16saabs is offline
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make sure the pipe on top of the turbo is in place , I had a similar prob after/during an overtake, I could drive the car easily by feathering the accelerator but foot down, no accelreation, & car died, I found the pipe had blown off, but as soon as the pressure(min) from turbo was applied, it lifted off the top of turbo, so then was sucking external air, but when revs dropped it just dropped back to rest on top of turbo, and it was only because I saw the newer metal that I noticed, as I did a carb spray all over and no response on tickover
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Old 23rd December 2012
Geoff Weeks Geoff Weeks is offline
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I guess I just don't "get" the probem... AN auto trans is not supposed to "rev" in gear while not moveing, Its called the stall speed of the torque convertor. 2000 RPM sound about right for a stall speed. So what is the problem?
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Old 24th December 2012
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Geoff -- the stall speed of 2000 sound about right to me as well. But my issue is that it wont rev up in gear while moving. It will still only go to 1500-2000 I may try lifting the front end enough to get tires off the ground and see if it will rev up higher with no load on it. I was using the 2000 rpm stopped and building boost just to let people know boost is building ok.
16saabs -- I will check that hose tomorrow or sometime this week. Your talking about the hose that goes from the compressor side of the turbo to the APC valve correct?

Also a question for anyone who would know is I rebuilt my engine and I can't remember if I did a glaze bust/re-cross hatch before i put everything back together so if I didn't would that possibly cause these issues? I remember it still had cross hatching on the cylinder walls when I took it apart just not sure if I glaze busted/re-cross hatched the cylinders or not and if not possibly the rings aren't sealing properly?
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Old 24th December 2012
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A compression test will tell you how the rings/valves are sealing.

A clogged fuel filter/line will limit top end while driving. Fuel pressure and volume test should answer that.
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Old 24th December 2012
16saabs 16saabs is offline
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Jason, re hose, I was referring to the hose that goes to the intercooler, but I also thought you were referring to a 5 speed box not the auto, butBanman's fuel supply is also another possible, as it could be the pump going, and it can only supply enough for 2k revs when under load, as any car will rev easy without load even with low fuel supply, as there is no rersistance from the drive to make it work harder
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Old 24th December 2012
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You really must check fuel pressure otherwise you are fumbling in the dark. Ideally you check pressure under power. Failing fuel pump can give exactly the symptoms you describe.

If you don't have a pressure gauge, measuring the fuel flow volume can also give indications of a failing pump. You should be seeing at least 3.5 LPM.
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Old 24th December 2012
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Could being low on gas cause these problems then? I know Im really low like maybe a gallon or 2 in the tank.
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Old 24th December 2012
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Originally Posted by JasenMorrow View Post
Could being low on gas cause these problems then? I know Im really low like maybe a gallon or 2 in the tank.
I wouldn't have thought so, but there's always a first time. Easy to find out - put some more gas in.
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Old 24th December 2012
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Ok. Ill try that as well. Got to wait till later today though as we have family coming over for dinner and stuff. Oh and I also broke a bolt on the intake manifold the one that is the very end on the front side of the engine. The manifold seems to be sealed ok and doesn't seem to be leaking from there but could it be leaking a small amount and causing the same problems?
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Old 25th December 2012
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Originally Posted by JasenMorrow View Post
Ok. Ill try that as well. Got to wait till later today though as we have family coming over for dinner and stuff. Oh and I also broke a bolt on the intake manifold the one that is the very end on the front side of the engine. The manifold seems to be sealed ok and doesn't seem to be leaking from there but could it be leaking a small amount and causing the same problems?
an exhaust leak *if you do have one) should'nt cause loss of power especially to that extreme, something else is wrong
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Old 25th December 2012
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It would be an intake leak and it would explain why i had low vacuum and low performance.
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Old 26th December 2012
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Originally Posted by JasenMorrow View Post
It would be an intake leak and it would explain why i had low vacuum and low performance.
Have you done the carb spray test around engine while it is running
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Old 26th December 2012
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Yes I have done that and there were no changes in running speed or anything
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Old 26th December 2012
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Are you saying it will accelerate smoothly, shifting through ranges until it reaches 2K and then flattens out? What happens if you don't put it in D and just hold it in a gear...will it also run until 2K and then flatten out? That would certainly sound like a fuel pressure issue.
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Old 31st December 2012
JasenMorrow JasenMorrow is offline
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Ok so update. I figured out my valve timing was off. Corrected that. Checked fuel pressure while running the car. Went up to 35 PSI and then stayed around 35-40 PSI car will rev up past 2000 RPM now but only very sluggishly. I set my ignition timing to 10 degrees on boost. The way I set it is i used a bike pump with an adapter to pressurize my vacuum advance/retard module to my planned 15 PSI of boost. Made sure it held pressure. This brought my base timing to 20 Degrees off boost as i have done the vacuum advance mod. My idle is steady at approximately 900 RPM which is in specs for the 850 + or - 50 RPM my vacuum is a little low at 12 inches instead of the 15+ that should be normal IIRC. When building revs I can hear the turbo spool up. I am 90 percent sure that I have no vacuum leaks. Have a very minor exhaust leak though. I will double check for vacuum leaks tomorrow. I have a FMIC installed so I will also pressurize that to about 5 PSI to check for any leaks there. Also will double check piping pre-turbo for any splits or leaks. I need a new check valve for on the PCV system which i should be getting tomorrow or may have one laying around i can use. I want to triple check my valve timing though. The way I set it was set my engine at TDC via timing marks and line on flywheel cover. locked it in place so it couldnt move. Set my exhaust cam up so that the line on the gear was perpendicular to the head then set my intake cam by lining up the gear with the 16th tooth so that the line on the gear was also perpendicular to the head. Did this with an actual 90 degree carpenter square to make sure it was dead on. Then I installed the timing chain tensioner. Double checked the timing marks to make sure everything was still in line. Rotated the engine twice by hand. and the Timing marks all still lined up. This is correct from everything ive read and done in school as well. (in automotive rebuilt engines last year) So if everything is set correctly and have good fuel pressure the only real thing left would be a vacuum leak correct?
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Old 31st December 2012
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I have no idea wether the way you have timed the car works,, as if the std setting is 12 deg, the advance and retard, and ECU shouild do the rest??? but for the car not go over 2k revs is something more than a vac leak, is it an air intake prob, blocked filter, blockage in intercooler?? I'm guessing.
undo your distributor, and get someone to apply some revs whilst you move it one way or the other to see what imporovments you might get
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Old 31st December 2012
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It will rev over 2000 now just very sluggish getting there. The only thing I can think of is either vacuum leak or some pre-turbo post AMM air leak. The intercooler was flushed and dryed before installation. All piping was pressure tested best I could do and they seemed to hold pressure. The way I timed my ignition is what several people suggested an various other threads on here as it is the only real accurate way to get the proper retard on boost other than a more advanced AID or other mods like T5 or megasquirt.
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Old 31st December 2012
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I only have the LPT but when I did the wife's HG I was a tooth off the timing, but it ran ok just did'nt have as good acceleration (for obvious reason lol), but still went up the rev range, just not as quick, the only other time I have had accel probs was when the top pipe blew off the turbo(to intercooler), and it rested back on top of turbo on tickover so you could'nt see it, , but I could still accelerate by feathering to speed limit60mph but no chance of an overtake lol, so I think it's still down to timing, but it also sounds like fuel supply, was your pressure test taken before pressure regulator or afterwards, as I don't know if it can block up internally, as although you might have the correct pressure if the reg is jamming up it can only let a certain ampount of fuel through a tiny gap, yes I'm clutching at straws for you but, know I how frustrating what seems to be a simple pronlem solve turns out to be a nightmare,, and I'm sure it will be something stupid.
Re the timing marks there should be no need to use a square, as the marks should line up with the nicks on the casting, and they are a bit of 90 deg, so you may have both cams off line,(a tooth) can you take a pic of your 'line up'
another try, try bypassing the T I/C see if it helps?? as althopugh cleaned out once you are getting prssure thete might be stuff inside that closes up
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Old 31st December 2012
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Are you sure you don't have a clogged cat or exhaust? Could have an effect similar to your problem. Never found retarded ignition stopped car revving, only gave low power.
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