Stock car was running fine and boosting strong and then suddenly it started bogging down real bad on heavy throttle up aound 3500 rpm and after a couple strong pulls into upper rpm range. Idle is ok and I pulled over and found turbo inlet air duct was real loose so tightened it. Still did the same thing tho but runs good with little or no boost and haven't checked air duct at turbo outlet or to + from I/C yet but hopefully something's loose there too. Any thoughts or since 1 duct was loose good chance something else came loose too right? Happened tonight so have to wait until tomorrow to check all connections. Other than loose air hose connections and loose plug wires + plugs what else should I check? Just bought the car 2 mths ago and havent't checked everthing over good but boost has been strong with no problems.
Car bogs down real bad on boost @ 3500 rpm
91Bluebird
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Stock car was running fine and boosting strong and then suddenly it started bogging down real bad on heavy throttle up aound 3500 rpm and after a couple strong pulls into upper rpm range. Idle is ok and I pulled over and found turbo inlet air duct was real loose so tightened it. Still did the same thing tho but runs good with little or no boost and haven't checked air duct at turbo outlet or to + from I/C yet but hopefully something's loose there too. Any thoughts or since 1 duct was loose good chance something else came loose too right? Happened tonight so have to wait until tomorrow to check all connections. Other than loose air hose connections and loose plug wires + plugs what else should I check? Just bought the car 2 mths ago and havent't checked everthing over good but boost has been strong with no problems.
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Just checked all turbo + intake connections and spark plug + wire tightness and everthing's good. Took it out on the road and car runs perfectly fine until 7 lbs boost then engine breaks up bad and have to let off the boost and then car runs normal again. Idles good too so does anyone have any thoughts, thanks.
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what gear is the happening in?? Can be a fuel cut or boost leak. my car did the same thing. It happened to be a fuel cut
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Only tried getting on the boost in 2nd, 3rd + 4th gears and at the same point around 7 lbs it bogs real bad like running on 2 or 3 cylinders but as soon as I let off the boost it's fine again.
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Did you tighten hose clamps or do a boost leak test? Its not the same thing. You could be leaking from injector seals or a shaft seal on the TB.
Your fuel pump could be going out.
Stop being lazy or enjoy walking. No reason not to have done the basic service in two months since you got it. How long do you think your car will last?
Your fuel pump could be going out.
Stop being lazy or enjoy walking. No reason not to have done the basic service in two months since you got it. How long do you think your car will last?
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Car was boosting fine like mentioned up until last night after doing a couple full boost pulls then prolem started and found air duct at turbo inlet was very loose (almost coming off) so tightened that down but still have the same problem now.
Plugs + wires are new and base timing is good.
Plugs + wires are new and base timing is good.
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The ones on top of TB or those other ones?
Can someone give me a link to building a boost leak tester?
Can someone give me a link to building a boost leak tester?
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2,224 Posts
I have to find out how to build a boost leak tester and check that.
I also was thinking about buying a used obd1 scan tool for these type of issues instead of swapping and checking every part whenever a problem comes up. Does anyone think that's a good idea, are there used ones to be had for cheap enough and are they fairly easy to use (I have factory service manuals).
Would a logger sufice for hunting down problems? Car is going to remain stock with max 14 lbs boost so don't really believe I need one for monitoring things and car may even remain completely stock so get a scan tool or a logger?
I also was thinking about buying a used obd1 scan tool for these type of issues instead of swapping and checking every part whenever a problem comes up. Does anyone think that's a good idea, are there used ones to be had for cheap enough and are they fairly easy to use (I have factory service manuals).
Would a logger sufice for hunting down problems? Car is going to remain stock with max 14 lbs boost so don't really believe I need one for monitoring things and car may even remain completely stock so get a scan tool or a logger?
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Went back out there and bypassed the boost control solanoid and boost did go higher than 7 lbs now before bogging down but still doing the same thing up around 10-12 lbs. Now I'm wondering whether the gas station guy mght have put 87 octane in instead of premium a few days ago but was boosting yesterday a few a times before encountering problems. Did not hear any knocking or pinging and I have ears that hear everthing but wondering if the ecu would retard the timing to such a dregree that bogging down would occur before hearing an aubible knocking. So thinking about getting a bottle of octane booster at walmart but don't kow if 1 bottle of 104 octane would offset 12 gallons of gas in there at 87 octane if that is the problem 
Did take the inlet air duct off turbo and felt no shaft play and it spins freely so happy about that and see no smoking out tailpipe and idle is great as is normal driving.
Did take the inlet air duct off turbo and felt no shaft play and it spins freely so happy about that and see no smoking out tailpipe and idle is great as is normal driving.
My car is doing the same thing. I think my BOV was leaking. It would let air pass at just 15PSI, Same point i have the problems. It is also vented. So waiting on a new one and it will be recirculated when hooked back up right. Hoping thats my problem
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Can someone tell me what the inlet size on 14b turbo is so I can get a coupler to make a boost leak tester.
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Well no more boost leak and the only thing I did was remove ISC motor + TPS THINKING I was going to swap in my N/T throttle body since thought the leak was at TB. Well seen N/T TB was not going to work I swapped back in isc + tps and reinstalled original TB and still had magor problems with stutter. 2 tanks of gas later absolutely no problems so thinking the guy might have either put regualar gas in car causing the problem -or- maybe re-intalling isc + tps and tightening them solved the problem but not sure.
Question is could 87 octance cause major stutering under full boost? I thought if anything knock would occur with low octane gas especially when heavy on boost but knock sensor would cause BCS valve to open limiting boost to 5-7 lbs like it's supposed to do when knock is detected instead of engine breaking up at around full boost acting like a major boost leak Perhaps my bcs is not working?
Anyhow happy I don't have to take my TB apart now and re-do all the seals
Question is could 87 octance cause major stutering under full boost? I thought if anything knock would occur with low octane gas especially when heavy on boost but knock sensor would cause BCS valve to open limiting boost to 5-7 lbs like it's supposed to do when knock is detected instead of engine breaking up at around full boost acting like a major boost leak
Perhaps my bcs is not working?Anyhow happy I don't have to take my TB apart now and re-do all the seals
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107 Posts
Using a analog volts meter i find is sometimes easier and cheaper. Or just get a datalogger and do your diagnosing that way, and they are necessity to use when you are tuning. And run 93 octane, that is so bad to do to your engine while running boost is to have 87 octane gas.
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I tried testing a tps and o2 sensrs with multimeter according to chilton's instructions and would up replacing good parts
I am planning on getting a datalogger but more for diagnosing problems rather than tuning because the most boost I'm going to be running is 14 lbs with real boost gauge + wideband o2 and figure that should keep me apprised of any troubles but idk maybe I'm wrong about that? Btw Is a FP re-wire necessary @ 14bs boost?
If your still having this issue I had exact same problem, turned out to be a simple fix of adjusting base timing and replacing the over gaped spark plugs, mine were gaped at .035-.04 they should be .028. I saw that you adjusted your base timing, and that you've had car for 2 months. Have you checked the plug gaps or to be safe I'd just replace them with new NGK's. Also have you checked for a exhaust leak before the turbo, I had a leak in my tubular manifold and when I patched it my spool up time improved ALOT? Also here's the link to make a boost leak detector http://www.vfaq.com/mods/ICtester.html And for pulling your codes if that's why you want an OBD1 cheaper way to go is to go to Radio Shack and buy a 12volt electric buzzer 2 dollars and some change. Also if your worried about fuel cut at 14psi on stock just rewire the fuel pump anyway pretty low cost and gives you that extra assurance. Also if your not worried about emissions do the emission vacuum hose delete, it will help eliminate alot of potential leak areas. When I deleted my extra hose's my idle leveled out. That's all I can think about at the moment I'll reread post and try to add more that may help.
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