If you ever decide to take another shot at it I will be glad to help you fix your truck. If not, I understand your frustration.


George

 

It sounds like you don’t have a lot of experience diagnosing and repairing vehicles but you found your way here so you took an interest in the process. The cornerstone of any capability for problems like your having is an ODBII scanner with live data capability and a basic digital volt meter. One of our moderators, Les wrote an article on inexpensive scanning capability with a blue tooth dongle and a smart device here:

https://blazerforum.com/forum/2nd-ge...24/#post734213

Amazon has any number of good low cost digital meters. A primer on 12V systems is found here:

https://blazerforum.com/forum/2nd-ge...59/#post732668

You can usually get a fuel pressure gauge loaner from a parts store as well as many other tools.

intermittent problems can be more frustrating to locate because you have to catch them in the act and it’s always better to confirm the failure before doing any work if at all possible. An approach to your problem would be similar to a crank no start issue because it’s the same potential causes unless it also won’t crank in which case you start with the crank circuit first:


https://blazerforum.com/forum/2nd-ge...rticle-103750/


If your done on this vehicle then maybe these suggestions might help you with the next one. If this one keeps staring at you daring you to fix it then we are here to help you. If all of this is not your thing then I understand and wish you the best of luck.


George

 

I actually have 5 cars, 1998 BMW Z3, 1952 MG TD, 68 MG Midget, 73 Lotus Europa Special, and this 1995 Blazer.

I do most of the work on all my cars, but I'm not a mechanic. I have very few specialty tools, just mostly basic ones. I spent my career debugging electrical issues in circuits so I do have some debugging experience.

Here are some issues.
The Blazer has a schrader valve for fuel pressure testing and so one has to buy the adapter because all of my friends have kits but no valve. Trying to order the correct one proved a bit problematic to figure out the right one get so I never ordered that. But looking at the spark plug and coil output while cranking during the starting issue that has now cropped up, there was nothing. So really didn't need to check the fuel pressure if there is no spark at all, right? Fix the first, obvious problem?

The Blazer has what they describe as OBD1.5, an OBD2 plug but pretty much OBD1. So a lot of scanners won't establish communication. I bought a scanner and it wouldn't. My mechanic friend's wouldn't. Autozone's wouldn't. A cheap one that goes through my phone actually does, but there are no codes to look at. When it fails, I'm often doing 65mph on a winding mountain road after driving for an hour so can't exactly be looking down at the readout while trying to find a place to pull out...

The problem started out as dying while driving after 60 miles or so, heat sensitive so you had to sit for 20 minutes then it would start. Then changed to not starting at all, then after I repaired the cam sensor plug, changed to severe power loss and running lean on bank 1 (which was obviously a code), and now has returned to not starting at all again.

Two mechanics have just turned down working on our Blazer because they claim they are difficult to work on and often have issues that are very difficult to debug. Hmm, exactly my experience.

 

I’m not sure what the issue is with being able to hook a fuel pressure gauge up to your Schrader port because my experience is that this is a common fitting. Again, a parts store can probably give you a loaner or sell you the adapter. That said, yes the ignition situation should be addressed first.

I am going to assume that when you say it will not start it always cranks? So now the question is why will it crank but not supply spark? The possibilities are: wiring/connectors, power or ground to the ignition module or the coil, timing pulses to the ignition module or out to the coil, the ECM, or a sensor input like the crankshaft position sensor. The easiest thing to check first is power and ground to the ignition module and fused power to frame ground for the coil when you have this problem. If you verify that you have a good clean power to both units when it cranks but has no spark then we move onto timing pulses.

A lean condition on one bank only is likely related to that oxygen sensor or one or more of the fuel injectors on that bank. That can explain the poor performance but is unlikely to explain a no run condition so you can hold off on that until you get reliable ignition.

I know intermittent problems are a pain in the butt but you have something going for you that a mechanic does not. You can travel with a digital voltmeter and a test probe and narrow the problem down as soon as it occurs. A mechanic doesn’t have time to drive your car around until the problem randomly occurs.


George