I can't seem to figure out why my 90 sho has no power. I replaced crank position sensor and got it to start and idle. I also replaced valve cover gaskets, plugs, and wires. The car will start and idle. Idle sounds rough and could be because mufflers are shot, but car almost seems to shake a little. When the car first starts it will rev up to about 4k in neutral before it starts sputtering but after warming up only about 2500. It has absolutely no power and barely drives around in 1st gear. The only way I can get it to move is slowly press on the throttle. If I punch it the car will die but will restart with no problem. Possible cam position sensor? Coil? I also unplugged maf and car runs worse that way. Any help or opinions are greatly appreciated! Thanks
Bogging problems 90sho
- Thread starter barnfind
- Start date
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Pull your codes and see what it shows. Did you try shaking the Y-pipe to see if the cats are plugged
TimboSHO
Intermediate
Make sure your plug wire routing is correct. There are manuals that have it listed incorrectly.
http://www.shoforum.com/showthread.php?t=69573
http://www.shoforum.com/showthread.php?t=69573
I used a mastertech scan tool and got codes for koeo: 24 IAT/ECT sensor pinpoint DA1. Koer: 22 IAT/ECT sensor pinpoint DA1, 25 ks or ks ckt pinpoint DG1. I checked plug wires and they are correct order. Also disconnected y pipe and seems to run a little better, but I did not drive around with it disconnected. I have cleaned all grounds on the car very well.
the 24 code for intake air sensor out of range must be corrected - I have seen this on a few of these cars and the engine will never run right with that code. most likely it is a wiring or connector issue rather than the sensor itself, but you must find and fix it.
I checked the air intake temp sensor and looks to be fine so it's going to suck looking for the broken wire. Also the scan tool I used said to advance timing 20 degrees. I can't figure out how to do this or does that mean the timing belt has slipped? Thanks everyone for the advice this far!
93VantuckySHO
Member
I'm not sure where the IAC is on this engine yet, if you can, unplug it and see if anything changes. You could also try that with the MAF to rule it out. I would think if there is no change you have found the culprit.
Does the idle hunt at all? Might be a vac leak, I always start at the PCV valve line. How are the oxygen sensors?
Does the idle hunt at all? Might be a vac leak, I always start at the PCV valve line. How are the oxygen sensors?
the intake air temp sensor is in the air filter box. you cannot just unplug it - every SHO I have seen with the iat sensor unplugged ran like crap. you have to make sure that the sensor and the wiring are okay so that the computer knows what the air temp is that it is working with.
93VantuckySHO
Member
Sorry I meant Idle air control.
you cannot manually control timing on this engine. If you disconnect the spout connector, then the timing will be fixed at 10*
the warmed up engine should barely idle at around 500-600 rpm with the iac unplugged. if so, you know the throttle plate is adjusted properly. however, this means nothing until you resolve the iat sensor code.
the warmed up engine should barely idle at around 500-600 rpm with the iac unplugged. if so, you know the throttle plate is adjusted properly. however, this means nothing until you resolve the iat sensor code.
Adjust the throttle plate by connecting both vacuum ports on the throttle body together and disconnecting the IAC. Then turn the plate screw until reaching the desired idle speed.
on an engine that has no codes, unplugging the iac should result in an idle speed of around 500-600 rpm. you do adjust the plate stop screw to get to that, but you cannot do it when you have codes that cause the engine to not run right.
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