vaccum problem????

superweasel

Registered User
was wandering if anyone has had this problem. when I shift my coupe into gear it stalls the motor to the point of stalling (or sometimes does stall it) and then the motor reves to about 1200 rpm's and then goes back to normal. does not do it when pulling out of gear to neutral. can rev the motor and put it into gear and the motor is fine.
 
more info would be good!! year , 5spd or auto ? however if you suspect vacumn leaks ,start the car and spray carb cleaner at the connctions on your upper and lower IC tubes , if your idle changes than you have a leak and need to reseal the tubes with a bead of copper rtv.
good luck
 
this car is a 89 with a 5 sped. i have already resealed the entire supercharger assembaly and can not find any vaccume leaks not saying that there are not any i just can't find them. the car does act as if it has a large vaccume leak when it is at idle though. It will run smoothly and then it will stumble and the vac/boost gauge will show a major vaccume drop and then it will rev high and cycle this way. This problem is dose not occure all of the time though.
 
I think that my MAF is bad (it is cracked across the top ) but I cannot find a test for it and when you pull the cannection of and the motor is running it really makes the motor run bad and when ou plug it back in the motor runs about as normal as it does any other time. coulds you give me the number on the MAF you are useing. this car is all stock except a really bad home made true dual settup that needs to be fixed and a set of steep gears.
please explain the motor mount. how would it being broken make it run rough and try to stall. has new plugs and wires already. I wish I could tell you guys the whole story on this car but it would take to much time so thanks for any and all your help you guys give
 
Just get another MAF first, from the Ford bone yard or Classified, Wanted board and ask for your year MAF w/electronics (be clear so you get the right thing), they are real cheap cause most guys are upgrading anyway and will trip over each other to sell you 1.
When your motor mount is broken the engine will bounce up & down and may not idle right. Open the hood, quickly rev the engine, if it moves more than 3/4" it broken but to be sure, you need to jack the engine up and inspect. Mine was in 2 pieces, metal to metal. Broken mounts affect idle more on AOD than 5speed. good luck
 
the car also stumbles when you go to give it gas and it does his every time no matter what. You have to feather in the gas so theat the motor has time to catch up. I know these are probable very stupid uestions but this is the first supercoupe I have ever owned and worked on in more tha a tune up sort of way.thanks for all of the help nd understanding any help with testing these components would be very helpful.
 
drive it around without the maf connected. It will set the check engine light but still tell you if the maf is the problem. It might take a few minutes to get it stable. Don't unplug it with the car running, you might damage it.

Is the aluminum housing or the plastic cover on the electronics? If it's the plactic cover then after a while mosture will corrode the electronics and give you bad readings. If the body is cracked it could give you bad readings from unmetered air.

Jeff
 
You can check the Maf connected with a volt meter. Select DC volts, lowest scale. you will have to stab the C & D(it has then embossed on the maf connector) terminals on the connector if all else fails use a stright pin through the insulation. it should be about .6V at idle and should increase with speed. It should be steady with engine speed. Watch for a sudden increase just b4 the engine stumbles.

Jeff
 
thanks for the testing info. the car always has a check engine light on but it goes out some times when i drive it . I dont get to drive it much since the syncros are out of it and the weather here has not been the greatest(as you all know it is not a snowbird) I cant get the codes to read for some reason even with the home tester from autozone. hopefully I can get it on a profesional tester very soon. thanks again
 
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