themcguire

Driving down the road...just died! Starts right up when fuel added to the carb manually. So, I put a new fuel pump...still will not run!

Is it the ECM ? or some sensor? I do not know what to replace next.

Any suggestions ?

EvansBlue

I have seen this happen more than once and I have to advise you NEVER to add gas to a carb manually. Use starting fliud that you can spray from at least 3 ft away.

Is your accelerator pump spraying fuel in correctly? Might be one thing you want to check. Apart from that, it could be that your throttle position sensor may be out of whack (if equipped).

themcguire

Thanks for the advise ... I was very careful. Used a pump to shoot the gas in because it was late at night and I did not have starting fluid. I know the danger.

So are you suggesting that I replace the throttle position sensor first, assuming fuel is getting past the injectors ?

Could this problem just happen while I was drving along the highway at 45 mph ?

EvansBlue

Hold the phone. I think I may be misunderstanding you. Is this throttle body injected (TBI), or carbuerated?
You just mentioned injectors...

The injectors or a simple fuel filter may be to blame here if thats the case. Things clog up. Did it shudder before it cut out? or did it just simply shut off?
Have you ensured that the injectors are spraying?

themcguire

Yes this is TBI. 1988 K5 Blazer - 5.7L (350ci Jasper rebuild)

I have now replaced the: fuel pump, fuel sending unit, filter, fuel pump relay, and TPS. I shot compressed air through the fuel line from the pump to the filter. (See below also replaced Ignition control module)

Still will not start, no fuel at "carb".


MORE INFO 11/09/2009

Replaced the ignition control module...sent 12v to red wire on the fuel pump relay (I am told this bypasses the relay) Now get 12 volts at fuel pump.

I should have mentioned that the truck runs as long as I spray starter fluid into the throttle body. To me this rules out the plugs, coil, distributor components.

Still no gas at the injectors...(Note; This problem started when just driving along and the truck died!!!!!)


UPDATE 11/10/2009

88 K5 still will not start - Could it be a safety switch?
<HR style="BACKGROUND-COLOR: #c2c2c2; COLOR: #c2c2c2" SIZE=1><!-- / icon and title -->I connected the fuel pump directly to the battery and disconnected the filter. Fuel flows to the filter.

I disconnected the fuel line to the back of the throttle body and shot air through it Air flows - apparently no blockage.

Someone suggested a fuel pressure reglator but I cannot find one. Fuel line flows from tank directly to throttle body via the filter. Could the fuel pressure regulator be part of the sender unit (Sender unit is new also) I do not have any floors or fenders on the truck right now total rebuild pending so everything is exposed.


Another issue I had forgotten until now ----

This truck was towed by the police for being on the street too long -49 hours. They did not have the key so they disconneced the linkage from the trans. When I had it towed back home the driver reconnected it.

However, I can push this truck forward and back while in park. I do not know why and was putting this off until I got the body back together.

Like I said it will run with starting fluid but not stay running. I thought that if it will start with the starting fluid then it could not be the Park /Newtral safey switch. But could this have been messed up when it was towed?

Any ideas...

themcguire

I added more info via editing. Please take a look at my prev post and advise. I wrote this so the date would change.

nauticstar87

maybe the injectors are clogged. if no fuel is getting down into the throttle body but the lines from behind the injectors back are clear, gotta be the injectors.

themcguire

But would both injectors clog at the same time ?

nauticstar87

It can happen. There are injector filters, i'm not sure where their at. you can get a TBI rebulid kit for around 50 bucks. It comes with gaskets, o-rings, injector filters, and regulator diaphragm. pretty much everything but the injectors.

rubrhammer

I'm not real familiar with the TBI units but I know that the Gen 3 engines have fuses for the injectors. Is it possible that there is a fuse for the injectors on yours and its blown?
Bob