Last post on Jul 16, 2013 at 4:58 PM
You are in the Chevrolet Blazer
What is this discussion about?
Chevrolet Blazer, GMC Jimmy, SUV
Go to NHTSA to file a safety complaint.
Or call Monday-Friday (8 am to 8 pm ET) (888) 327-4236 TTY: (800)424-9153
#2951 of 3676 Re: 1990 GMC Jimmy idle and loss of power problems [pinchot13495]
Mar 25, 2007 (6:20 am)
Advance and Autozone and most stores will read the codes for free (this assumes the SES light is on so a posted code). They also have a free handout that tells you how to read them out yourself cause thus is a 90 so believe old system and you can get the light to flash the code out. Very common is the old CPI and nut kit which is the injection under that upper intake - it leaks and does what you stated so do a search on CPI and Blazer and you will find many answers.
Mar 25, 2007 (12:14 pm)
Thanks for the speedy reply repairdog. I see that you have been a great help to many. I've been pouring over my Chilton manual this morning trying to find any info on the CPI unit but with no success. I've done the search as suggested and have come to guess (probably mistaken) that CPI stands for Central Port Injection. My jimmy being a 1990 model is equipped with the Rochester TBI unit. Would this still have the CPI and nut kit (supply lines)? Again, many thanks!!
#2953 of 3676 Re: CPI question [pinchot13495]
Mar 25, 2007 (3:53 pm)
Sorry, missed that 90 date. No CPI on the TBI models only the electric injectors on the throttle body. You have the book so now check the fuel pressure to see if fuel pump related or relays.
#2954 of 3676 Re: CPI question [repairdog]
Mar 25, 2007 (5:23 pm)
No problem repairdog, figured that out this morning. have done a host of things mainly checking and re checking things in leu of having much to go on as far as diagnostic tools. I've noticed that there is no fuel entering the top left throat of the TBI. Is this the secondary? Noticed a pinched wire leading to the injector. Wire integrity seems ok, have insulated it the best I can. Have wired in a Jacobs FC 1000 ignition module and it starts with no problems so I can rule out any problems with the ignition system. I work at Mallory Electric so I guess I can talk to a few people there and maybe find out more.
Mar 25, 2007 (8:55 pm)
Iíve been having a front diff. actuator problem with my 4wd í02 blazer ZR2. With the vac. line above the driver side fender plugged in the actuator wonít engage below 35mph. While on the highway above 35mph (roughly) the actuator engages. It will not engage with the vac line unplugged at that speed. Are there any long term effects leaving the vac line unplugged while only in 2wd and does the speed have any effect on the vac switch itself? Is the vac switch the source of my problems? Thank you for any help
#2956 of 3676 Re: Actuator problems [3521bytrade]
Mar 26, 2007 (2:13 am)
Can't say for sure but if you disconnect the vac line under hood to the 3 port you must plug the engine side off (golf T is great). The 3 port switch on the case is about $20 so try that first (based on 3 button 233 case - tag on case - not the 236 4 button Autotrac case). Check all lines under and up to the front actuator that the vac engages and that pulls a cable to lock or coupler the pass side axle. Then at the same time (when you select 4Hi) the encoder motor on the case steps and engages the front driveshaft. So, once you select 4Hi axle couples and front shaft engaged and light on dash stops blinking and goes solid on 4Hi - if not the TCCM (4wd computer) did not get readings from the sensors on the axle and case confirming status.
#2957 of 3676 Re: CPI question [pinchot13495]
Mar 26, 2007 (2:29 am)
All mine are newer models so this is a reach back. The fuel pressure per Haynes is 9-13psi. Assembly has the throttle body and fuel metering controlled by the throttle position sensor(TPS) on the throttle butterfly shaft which signals the PCM that then determines the mixture. 1 injector is primary and 1 secondary as I recall (had a 350 Suburban TBI). Also an idle air control (IAC) on the TBI that maintains idle by air mixture. $15 Hayes shows most of this.
#2958 of 3676 Stalling problems
Mar 27, 2007 (2:33 pm)
I have a 04 chevy blazer 6 cyl 4 wheel drive.
I purchased in Jan 07. (39,000 miles)
Its been back to the dealer 4 times for stalling.
I'm just driving down the road and its shuts off.
I still have power but the engine quits.
so for all that has been done is (replaced)
the distributer cap and roater,the coil and something attached to it. They can't figure it out. I don't get any
check engine lites. Im pritty sure the problem is electrical,but who knows. Can anyone help this is driving me crazy.
#2959 of 3676 Re: Stalling problems [frschevy]
Mar 27, 2007 (5:20 pm)
Crank shaft position sensor??? If intermittent it will not set a code. But the fail mode is that it thinks the engine is not turning and will shut off the fuel and ignition. One way I have isolated it is to try this. When the engine quits, WITHOUT TURNING THE KEY OFF try and start the engine. If it will not fire, turn the key to OFF, count to ten seconds or so, then see if it will start. If it fires right up, you may have an intermittent sensor. I have seen this on late 80's and early 90's, but the discription you give does seem similar.
#2960 of 3676 Re: Stalling problems [jlflemmons]
Mar 28, 2007 (1:53 am)
I agree that is often the one - my daughters 01 just did that and I replaced the CPS (use a Delco or standard motors sensor - many others are slightly off and effect timing). Then also if that simple $60 part that takes 2 minutes to change is not it, look at the idle air control (IAC) valve on the side of the throttle body - its electric and controls the air to keep the idle stable - connector can be kloose or ther IAC or passage all full of crap. Then GM has had some failures in many models due to the PCM seeing a voltage drop in the ignition switch (actually the wires and connector in the column) that shuts the engine off. Often associated with blinker being on at the same time and only fix is replace that ignition switch (again not the key/tumbler). This last one is not common and only a real electrical guy has any hope of finding but the dealer should have seen info on this. If the other 2 fixes don't do it insist they replace the ign switch. Hope you are still under warranty. Post the final cure so all know please.