Hello, bought a 93 blazer, drove fine for a week then EGR acted up and died, threw EGR code, replaced it. Drove for a week and died again, this time threw IAC code, pulled it out, cleaned it no difference, pulled it again and measured shaft, out of spec replaced. No difference. Freind said check fuel pressure, rented gauge and tested it. Results showed pressure regulator and fuel pump bad. Opened plenum and gas was everywhere on regulator side, replaced spider. Dropped tank and inside tank had mud and rocks and a white colored fuel. Rinsed tank with water, replaced fuel pump and intake filter, also replaced inline fuel filter. Rebolted everything back together and did a full tuneup except timing (no timing light). Started blazer, it ran worse had surging idel now and dies if placed in gear, TPS code thrown, pulled it and replaced it as it was worn pretty bad. Still surges badly on idle, began to think I may left water in tank poured in two bottles of heat and a total of 5 gallons of gas. Still surges on idle when it runs I can now shift it into gear but shifts hard and dies in a few feet also backfires in the intake, retorqued bolts on intake still backfired, afjusted timing by ear, no more backfire. Still un-driveable. Can water in the gas cause these problems, I'm at a loss, this is the first vehicle I have been unable to get going in some 30 years of working on vehiccles. (shade tree mechanic). Any ideas? I'm getting ready to drop tank and make sure it is bone dry before I put gas in it again. Please throw any ideas at me. Thanks.

 

Help my memory, does this year have a mass airflow sensor or a MAP sensor? Some vehicles have one, some the other.If it has a mass airflow sensor in the air intake tube disconnect the electrical plug and see if it runs better. If it runs decent then that is likely your culprit. Sometimes they can be cleaned with a "SPECIAL" cleaner made specifically for MAFs. Honestly only works about 1/3 of the time though. Todd

 

Sounds like it may still be a timing issue. Though water in gas can cause some of the issues as well. I would verify that it is timed correct.

 

Already cleaned the MAF, read about this issue with bad MAP sensor gonna bench test it tonite, if it resolves I will post reply so others may learn from my hardships, seems these blazers have this silly problem with the CPI versions quite common. Bad design, if it dies again i'm gonna carb the beast I swear, least they are easy to fix. having to replace the whole freekin fuel injection system a part at a time stinks and costs alot. Everytime I fix one part another fails, it's like a heart attack victim with clogged arteries having chain reaction problems. Thanks for replies and tips, will reset timing to facorty specs once it can stay running.

 

So you are going to bench test the MAP, or MAF? I would highly suggest just trying to run it with MAF unplugged and see how it does. Cleaning just won't fix a lot of them, and usually they run better on default values when uplugged totally. Not trying to beat a dead horse, but trying to make sure you understand what I'm trying to relay.

 

Well I'm confused! I thought a 93 with CPI didnt have a MAF.

And you reference a 'conversion'.
To what? Does your injector assy have 2 wires or 7?

 

I'm curious now too, I was somewhat thinking MAF didn't come till 96 maybe. The symptoms he lists are very similar to a failed one. But the OP has said he already cleaned it so I'm wondering if my memory is right or not. So do the EGR,IAP, and TPS happen to share a ground or 5v reference circuit?

 

Dunno cuz I dont have the diags but it's worth checking 5v and gnd ref on all of them.
Plus here's something I just posted on another thread, that may help