car not running right 87 gn

mikes gn

Member
Joined
Mar 3, 2005
i've looked for vac leaks and scan master #'s seem right.. if i'm just driveing along it seems to run fine, but start to give it some gas it'll stumble, hezatate or bog, but feather the gas it will then take off and run fine , untill i let off the gas. same when i stop at a stop sign, as i try to pull away it'll bog or stumble for a second or two and then takes off fine...
 
sounds like it's going rich, test fuel pressure(should be 43-45psi w/vacume line off) thats just a guess, it could be many things, you need to be more specific. and test the simple things first. if you have changed anything with the car recently, look in those steps also.
 
fuel pres. @ 42 but when i droped it down to 39 it did seem like it boged or hezatated a tad less.. which s.m #'s should i be looking at when it bogs or stumbles??.........thanks
 
ok, look at the o2 voltage when the car is doing this. it should be 800-840 or so during spoolup....if its over 840 or so then that would indicate rich. make sure the o2 sensor is good, because if they are bad it will give false info. i would go buy a denso sensor and put in there. just to make sure
 
i put a new o2 in last year and only put on 250 miles at must, what do i adjusust to lean it out if to rich??..............thanks
 
what kind of MAF do u have, stock? if u have a spare MAF sensor laying around u could try to swap it and see what happens. i had one go bad and when i was driving real slow it was fine but when i put a little load on the engine it fell on its face.
 
i went threw 2 rebuilt stk maf's and the car would idle untill warmed up and die, so i went with a lt1 maf w/a translator car now staying running when warmed up, but has the stumble or bogs when you first give it gas. my o2's drop real low when this happens but quickly rise back up.
 
well, if the o2's are going lower...then it's going lean. you need to add some fuel down low. put the fuel press at 43psi line off. what kind of o2 readings are you getting when it stubbles? translator pro, plus?
 
it's the plus,, and i lowered fuel pres. from 42 line off to 38/39 and it seemed to stumble less but not much, i'll play around with fuel pres, but what else should i look for as for as #'s go on the scan master.. the o2's drop off just like after you floor it they drop real low and then pick back up, but some times it will 0 out and or around 100..
 
hmmm, well...you need to put the fuel press at 43psi and leave it. you need to get another o2 sensor in there cause it sounds like that one is going out. i don't think it will fix your problem, but you need it to help tune the car! what are the settings on the translator at? did the car run fine one day and all of a sudden do this? or did it do this when you put the translator on?
 
it started doing it after a turbo,injector chip change so i then bought all new stuff and what it would do is start up fine run great untill it was warmed up then just die..........then i added new fuel filter and o2 sen... still did the same thing..........was told it sounds like the maf so i ended up buying 2 rebiult ac delc stk ones......still did the same thing........so i bought a lt1 maf and a transltor car now stays running but i have this bad stumble or bog what ever one would call it.........after i posted all my sm #'s they said the seem to be in order..........so i'm lost
 
what chip,inj, turbo? i need to know whats on the car. what settings do you have adjusted on the translator right now?
 
i had a tt chip for 100 octane, but i took it out and replaced it with a reds 93 chip as i had no way of getting 100 octane at the time but the car runs the same with both chips...
mods and car
87 gn 53,021 org miles
after market fuel pump
hot wired
k&n open air filter
adj fuel reg
after market exhaust
42 lbs inj
te44 turbo - translator came pre set


i have my old sm #'s but tonight i'll get all new #'s one at idle warmed up and one set of #'s just as the car stumbles, and hopefully that will get me the help i need to get it running so i can enjoy the car when i drive it.. or just hope these cars keep gaini=ng in $ and just sell it when i can turn a good profit........oh well thanks for any and all help,mike
 
i think some #'s to pay attention to when the car stumbles are BLM and Integrator. both should be around 128, i believe higher # means car is adding fuel because it is lean, lower # means car is removing fuel for a rich condition.
 
i had a tt chip for 100 octane, but i took it out and replaced it with a reds 93 chip as i had no way of getting 100 octane at the time but the car runs the same with both chips...
mods and car
87 gn 53,021 org miles
after market fuel pump
hot wired
k&n open air filter
adj fuel reg
after market exhaust
42 lbs inj
te44 turbo - translator came pre set


i have my old sm #'s but tonight i'll get all new #'s one at idle warmed up and one set of #'s just as the car stumbles, and hopefully that will get me the help i need to get it running so i can enjoy the car when i drive it.. or just hope these cars keep gaini=ng in $ and just sell it when i can turn a good profit........oh well thanks for any and all help,mike


I think 42# injectors have a real nasty reputation of having that dead spot... or stumble....

If your Eric Marshall chip was also for 42# injectors... I'd send it back and have him fix it.... (especially if you got Red's chip to ride around on) These cars are just too nice not to fix thos pesky drivability issues.... it ought to idle and drive fine.
 
ok, i put fuel pres back to 43lbs line off, car now idles kind of speratic almost dieing then i't picks back up and idles's awhile nice then almost stalls but won't. it idle'd way better at 39 line off..#'s on warmed up

02 - 160 - 625 low was when it wanted to die out
af - 07
bta - 13.5 - 13.8 moved abit
int - 124
bl - 90
clt -170
ats - 92
rpm - 850 but went low when it almost dies
tps - 44
cc - 235 but moves around
no mal codes show up even after the speratic idle
sorry no driveing #'s i was unable to drive today


eric, knew when he burnt the chip it was for new lucus 42's
 
before all of this the chip was changed out with out disconnecting the battery, could that be a prob. with the ecm???.. i'm now graspping at straws.
 
When you drive the car, make sure TPS voltage goes up. My TPS sensor showed correct voltage with key on and car off, but under load I found the TPS sensor was bad. Also, maybe try new spark plugs and/or wires. New plugs and wires can cure a lot of problems. I have the same injectors and also Eric's chip-no stumble here.
 
i already changed plugs and wires, i'm hopeing i can drive tomorrow and i'll post all sm #'s when it stumbles.
 
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