'89 GMC Sierra 3500-454 engine-starter ??'s

[loneponie]

Hi Chevy & GMC Gearheads;

I'm a horse gal in Southeast, VA who's new to this forum. I have a few questions regarding my 1989 GMC Sierra pick up. It's a 4x4 3500 series with a 454 engine. Here's a little background in case in matters: It has 82,000 actual miles on it, but it's obviously 20 years old. Former owners had it in Northern, VA where there's a lot of salt on the roads in the winter. Most recent previous owner is a friend and horse gal who was a little less mechanically inclined than I am. She had lots of parts replaced on this truck, but could never get it going like she wanted. So, I inherited it.

Current issues: 1) Engine was running hot around 240+/- but not in redline. My brother replaced the T-stat and it's now in the 210 range. The hot engine caused other problems which been addressed. However, thought you should have this background in case it's a factor. When I started this engine cold, in the past it always started. After the engine runs and gets up to temp, i.e. I go somewhere for longer than 15-20 minutes, it doesn't want to restart until it sits for a while. That had been the pattern. Now, despite the new T-stat and cooler engine/under hood temp, it sometimes doesn't want to start cold. Sometimes it will start after it's up to temp when I shut it off and then start it up several times. Othertimes, no. So, it's sporadic. I've determined that the battery is charged and that cables are tight and no corrosion. So, what else should I look at? Is it likely that my starter is dying or do they just live or die? If so, is a loose wire likely?

2) Dash board brake light blinks 7 times in sequences. Where can I find out what this code means? Local shop checked out the brakes and system to say that they are working fine and it's 100% safe to drive & pull my horse trailer. Then they mentioned it's probably ABS related, but couldn't tell me what the code means.

Any help would be greatly appreciated. I did search the other forums using the search function, but didn't find this mentioned already. If it had been covered, please pardon the redundant questions.

[ImportThis]

go to a local parts store, and git a 5 prong relay kit and wire it up at your starter solenoid(they should be able to give you a wiring diagram). you will need a crimping tool and a couple cable ends to do this. i usually use spade connecter to connect the original kick-in wire to the switch side of the relay, and zip tie the relay to the solenoid, that way if you remove the starter the relay will come off with it.

after 10 or so years, the wiring starts to break down, and when the engine gits hot the wire will not carry enough voltage to kick in the solenoid. it is a very common problem on late 80's early 90's chevys, toyotas, and nissans.

i hope this info helps ya

[ChevLoRay]

from the Heart of Arkansas! You have found the right place to get the help you need, at least from a technical point. Some of us would have a long drive to give physical help. Anyway, there are folks on here who have the know-how and the ability to tell you how to check and what to check and what you should be seeing during those checks. So, hang on girl. It's gonna be alright!

[ChevyTech]

Welcome to the message board.

Re: issue 2

If the instrument panel brake indicator light is blinking you need to check the Antilock brake system for trouble codes.

If I remember correctly, on the 3500 series (1 Ton trucks) the rear wheel antilock system is referred to as ZPRWAL which is very much like RWAL. I cannot remember if this is the case on all 3500 trucks or just the ones with heavy duty brakes.

RWAL which stands for REAR WHEEL ANTILOCK. RWAL was standard equipment starting in 1988 on full size trucks. I think your 1 ton truck will have the ZPRWAL system which is very similar.

ZPRWAL on 30 series HD models have a different procedure for clearing codes.

I looked at my RWAL manuals and can not find the differences in these two systems which is frustrating because I know I have information on it. I you have a good digital ohm meter and know how to use it I am fairly confident we can find the problem. Let me know if you want to dig into it.

There are very few people that know much about this system.




I am fairly sure this information below will match your truck;



FROM THIS POINT ON I AM USING SAVED NOTES FROM EARLIER REPLIES AND WILL REFER TO IT AS RWAL.

1988 and newer trucks that do not have 4 wheel ABS have RWAL.

The RWAL system can store trouble codes, but it is only capable of storing one code at a time.

The manuals state that even if the light is blinking you should read the code with a scan tool or by using the ALDL connector.

You can retrieve RWAL codes without a scan tool.

To retrieve RWAL codes connect a jumper wire between terminal H and terminal A of the ALDL connector with the key on (engine not running). Watch the dash brake lamp and count the blinks. Sometimes RWAL system send out a phantom blink before the code blinks start. It can take up to 20 seconds for the code to start coming out.

Checking the code with this method can set a false code 9. Checking for a code when no code is present sets a code 9.

It sounds like it has a code 7
If you get one long flash and 6 shorter flashes that is a code 7.
Code 7 = Shorted isolation valve or defective ABS module

The isolation and dump valve are in the same part. It’s located out by the master cylinder. The isolation/dump has 4 wires going to it and has two solenoids on it. The combination valve has one wire going to it and is more long and skinny.

Let me know if you want to start testing parts.

[Locknkey]

Replace the starter and you'll have no more problems with it. make sure the heat shield in still there above the starter or the starter will get back to its old habits again later on....

[dan76]

By not starting, do you mean the (1) starter engages but the engine does not fire.... (2) starter does not engage but issues a high pitched whine without turning the engine....or (3) the starter turns very slowly?

1. usually means a vapor lock in the fuel line...but since your engine is probably a TBI system this may not be the problem. However check for a fuel spray in the venturi when the throttle cable is pulled. Do this with the air cleaner off so you can see down into the throttle body.

2. The bendix is not engaging properly......replace the starter with a quality rebuild or new unit. Be sure to check for any shims between the block and starter when removing the old starter....you'll need to reinstall to ensure proper engagement between the flywheel and starter gear teeth.

3. The starter is heat soaked causing high electrical resistance. If you can... install a heat shield between the exhaust and the starter body. I've used a flattened coke can for a temp fix. One can also wrap the exhaust by the starter with exhaust wrap. This will work nicely if headers were installed by a previous owner.

Cold starts are another matter. Check plugs, plug wires, rotor/cap and replace as necessary. On TBI engines, hard cold starts are usually caused by a faulty coolant temperature sensor. Check it for a loose connection. A Haynes manual will tell you where it's located. For plug wires, go to NAPA and get their guaranteed for life wires. They will replace the set no questions asked if a future problem occurs. Also replace the fuel filter....usually it's long over due on older trucks.

Chevy Tech is correct about the RWAL. It's best to get the system working correctly if possible since it will help you avoid rear wheel lockup when towing on a wet surface.

Good luck.