Need Help! 1987 R10

[dbarber608]

Hello,

I own an 87 R10 with a TBI 350. I was driving the truck without any issues when suddenly, while going up an incline, it backfired so hard that it blew the muffler apart. I had it towed home and tried to crank it, but it wouldn't start. We tried using starting fluid, but it didn't help. Suspecting an issue with the ignition system, we decided to replace the distributor and coil. This allowed the truck to crank and run, although it was running rough. We adjusted the timing, and it seemed to improve.

However, after getting it to crank, it would idle for a bit and then go dead. Holding the gas pedal down kept it running, but it continued to run rough. After reading some posts online, I suspected a problem with the TBI unit, so I purchased and installed a new one. Unfortunately, the issue persists. I checked for vacuum leaks and replaced a few cracked lines, but the truck still runs rich and stalls out.

I would appreciate your advice on the next course of action.w

Thank you,
David

 

[ChuckN]

Have you checked the ignition timing?

 

[YakkoWarner]

Hello,

I own an 87 R10 with a TBI 350. I was driving the truck without any issues when suddenly, while going up an incline, it backfired so hard that it blew the muffler apart. I had it towed home and tried to crank it, but it wouldn't start. We tried using starting fluid, but it didn't help. Suspecting an issue with the ignition system, we decided to replace the distributor and coil. This allowed the truck to crank and run, although it was running rough. We adjusted the timing, and it seemed to improve.

However, after getting it to crank, it would idle for a bit and then go dead. Holding the gas pedal down kept it running, but it continued to run rough. After reading some posts online, I suspected a problem with the TBI unit, so I purchased and installed a new one. Unfortunately, the issue persists. I checked for vacuum leaks and replaced a few cracked lines, but the truck still runs rich and stalls out.

I would appreciate your advice on the next course of action.w

Thank you,
David

If you are running really rich, something is telling the TBI to crank the injector pulse way up. First place I'd look is the temp. sensor - if that goes bad it can definately make the TBI go ultra-rich (on my Suburban I tried to start it with the temp sensor completely unplugged one time, and it went so rich it couldn't even run).

After that the MAP sensor also has input into the system, and a bad vacuum line going to it could also make the TBI system go way rich. May not be the sensors at all - could be wiring going to them. I'm fighting with TBI electronic gremlins myself and have been for almost a year (opposite of your problem; running lean) - when it works its great and its normlly pretty bulletproof but it can't tell you what's wrong like a newer car so theres a lot of trial and error trying to get it right again.

Your bad backfire could have blown a head gasket - I'd consider a compression check to make sure everything in the cylinders is good.