OK guys, read all the DIY sections. Here's the problem. Not my car, doing work for wifes friend. Blazer over heated last week, I replaced the water pump, thermostat, and hoses. It's always has run rough I guess. So I did a tune up. She has to push accel. pedal to get it to start so I thought it was the TPS. No real change. I replace fuel pump last year on it when it failed. So it broke down the other day, running super rich with missfire. I noticed volt gauge rising till the point engine would die. Checked alt output, it would start at 14 then rise to 18 and kill the motor. I replaced alternator, problem fixed except the running rich and missfire with sulfer smell. I checked fuel pressure, 55-60 but when you shut off key, drop to 0-10psi instantly. Going to pull intake plenum today to check for fuel leaks. But upon driving it I noticed fuel guage dancing around just a bit. Seemed odd. I read that article on the grounding point on rear crossmember. Any other ideas would be great? will also clean MAF sensor and EGR today as well. Pulling my hair out on this thing. Any help would be great. Only codes are P0300 and plugs have black soot. Could the hi voltage from alt, make the fuel pump pressure spike blowing out regulator?

Thanks,
Dano

 

If the pressure bleeds off, there is definitely a leak.

Be careful. Too much rich running will clog the cat and cause you to pull even more hair out. That may already be the issue.

 

CAt is already shot, can hear it rattleing, but the rich, and running like its on 3 cylinders all happend after alt over charge issue. The fuel bleed off was obviously the issue with the hard start having to push on accel. pedal. Now to track down the rich missfire issue.

Ok think i found problem, regulator is dripping upon key on and off cycle, the spider tubes on pass. side look like a burnt marshmello, so should i replace hole unit? Need cheapest way to get this done.

 

MFI spider upgrade. DO IT! Search for "MFI+Upgrade" for part numbers & costs.

 

Got the MFI kit installed in about an hour or so and the thing runs like it's new, here I was chaseing a ignition missfire until I found all the great info on this site. Thanks swartlkk.

Have a new issue that didn't happen until the hi over charge from alternator.

1. The heater is blowing hot air and the vent door motors are continuesly open and close.

2. The radio will not work only shows clock.

Anyone heard of this issue from alternator pegging voltage?

 

Anyone help on this issue, or whats the sequence to reset the HVAC, radio shows stations now but no sound, HVAC cycles automatically between cool and hot.

 

With the HVAC, only the temperature door is electronic. All the rest are vacuum controlled. Do you have the manual HVAC or automatic? Both were available in '99 and the diagnosis is different for automatic.

As far as the radio goes, overvoltage could damage the radio. If you know someone else with a similar year truck (98+), you could try putting your radio into their truck to see if it works there.

Neither of these seem related to the topic of this thread, but it is your thread to begin with.

 

It's a automatic style system. Thought i saw a reset sequence mentioned somewhere.

Thanks.....

 

Search to the rescue! "HVAC+reset" into the search box turned up this thread down near the bottom of the 14 returned results:
AC Hot and Cold Question. Winner gets a Starbucks Coffee.