I have a 1997 Cali emissions truck. Having a hard time starting this winter in Missouri. If it is under about 40 degrees won't hardly start. It's like it "half" starts or something. A tiny squirt of ether will fire it right up, but I don't like doing that too often. My question is this. I tested my gpr and I had 12.88v into it and 11.3 or 11.7, can't remember for sure out of it. I also noticed in an earlier post that there is a plug in each valve cover you can test gp resistance at. My truck has two plugs not one and each has 5 pins not 8. Does anyone know how to test these plugs and what the resistance should be here. Also is the gpr bad with the lower voltage. By the way, I also get a ton of white smoke for a minute or so on idle after starting, but not if I plug it in . If I plug it in I get virtually no smoke and it starts great.

Thanks in advance,
Mike

 

Sounds like your relays tired, should be same voltage or really close on both sides, as for the either DON'T use it, if your GP;s were really working you'd be looking for a new air box or worse!

 

Will a "tired" gpr make a truck hard to start even at 40 degrees, also is there a way to check gp's without pulling valve covers?

Mike

 

Stick a fork in that GPR, it's DONE. That's more than 1V voltage drop, and the "it's done" limit is 0.3.

The earlier trucks (maybe all OBS?) have four 5-pin UVCH connectors as you've found. Each one connects to two injectors and two GPs. The far outside terminals (#1 and #5, if you're counting) are for the GPs. Test - disconnect the connector, put an ohmmeter on one outside pin on the gasket (other probe of the meter on the battery negative or other good ground). Resistance should be aprx. 1 ohm. Considerably less means the GP is drawing too much current. "Open" (infinite resistance) means the GP is just plain shot.

 

The cali will cel with a failure within the gp system.
A scan will direct you to the failure.

Bill

 

Isn't 12.88 volts at the relay a tad low, should we be at 13.5 ish volts????? Just thing from my own experience (see my recent thread) that these psd need top shelf voltage to fire.,,,,,,,,,,,

 

Presumably that was with the engine OFF; 12.5-12.8V is pretty normal for engine-off battery voltage.

 

Thanks for all the info. I will do some checking on the glow plugs and change the relay and let you know. My voltage was with the truck off. When I told a neighbor who is a mechanic about the problems I am having he steered me to think my comperssion is bad and that is what is causing the hard cold starts. How do you check the comperssion on one of these and will a regular comperssion gage work? Thanks for the posts and sorry it took me so long to reply, I have been out of town with the fam for Christmas.

Mike

 

Did it run well and start OK in the summer? If so I wouldn't think compression is the issue. Keep it simple and take one thing at a time. Change the relay and go from there.

 

It runs great in the summer and starts with ease as long as I plug it in when it is cold. I think it is gp's and/or gpr.

Mike

 

If the GPMS is still active in your truck.
The event of a gp or relay failure will set a cel.
I would change to lighter weight oil.

Bill

 

It does have a cel, has had for years. I cant remember the exact number, but it is gp monitoring system or something. After reading what some guys have been thru trying to get rid of that cel I haven't messed with it. Last winter it started fine with the cel. I probably do need to use lighter oil though. Because of how easily it starts when plugged in I belive I have a bad relay. I changed a few gp's a few years back (before I new about this site) and put in autolite's so they are probably shot.

Mike