88 C1500 dash gauges issues...

[**grumpy**]

Im a longtime member, usually in the 60-66 and 47-59 sections.
I bought a 88 C1500 standard cab, short step for my 16yr old. Well, its mine but he thinks its his..

Anyway, its a super clean Texas truck, V8, automatic

The motor sounds great, runs strong.

But heres the issues:

Wont charge. Changed battery, no better
Took alt off my 55 gmc which has a 89 350, tried it, no better.

Volt gauge reads about 10-11 then drops to 9-10 after driving.
Cranks hard, sometimes starts, sometimes wont. But then will start hours later or next morning...? Sometimes...
But if hook baattery charger up when truck running and hit boost, the gauge goes to 14v.

Then, oil pressure gauge shows 20-25 lbs when cold, but drops to 0-15 at idle, hot. Reads 0-10 and red gauge warning light comes on.
But motor sounds and runs good. No noises, ticks, knocks etc.

Then, temp gauge starts at 0 when cold, but goes to 195-230 once warm, and frequently stays over 220, but motor doesnt seem hot at all.

So I dont know WTH is going on with this poor truck.

We plan to do a flip kit, spindles/springs and wheels and make a cool ride for him/us 9mos of year for daily duty, swapmeets etc.

[Ricky78045]

Volt gauge reads about 10-11 then drops to 9-10 after driving.
Cranks hard, sometimes starts, sometimes wont. But then will start hours later or next morning...? Sometimes...
But if hook baattery charger up when truck running and hit boost, the gauge goes to 14v.

hey Tim, sounds like your truck has some similar electrical problems that mine had. I worked on my grounds, junction block cables reorganized, upgraded my battery cables to 2 gauge, and quite a few more things that helped my truck get back into running conditions. I still have some other electrical gremlins so I'll be posting on my thread anything I do to fix it. It might be a completely different situation but heres the link to the thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=517431

Let me know how it goes. Rick-

[**grumpy**]

Hey Rick
Thanks for reply.
Yeah, much of it was due to bad grounds.
After I changed alt. and battery, I decided to re-do the grounds...it worked

Except oil pressure.
It shows 30lbs at start up, but quickly goes to 0-10 while driving or at idle, but motor sounds great.
And if you shut off after a long drive, and restart within 10 minutes, its back to 25-30 lbs.

Motor sounds and acts the same no matter what gauge reads. No ticking, knocking etc.

Im guessing bad sender?

And temp gauge still ocassionally goes to the 210+ range but never acts hot.

[TennesseeZ]

do you have access to another guage you could hook up and compare with the one on it now?

[ChevyTech]

It is common for the oil sender to go bad making the oil gauge show a lower oil pressure then the engine really has.

[**grumpy**]

I grabbed a triple set of gauges at the last swapmeet for use in one of my old trucks.
I may hook all three up and see what they say.

Im near positive the motor is ok, because it runs very good, even when showing no oil pressure.

I'll get to swapping gauges after I get my 55 GMC in garage for winter re-do.

Thanks guys