MY TRUCK WAS RUNNING ROUGH AND WOULDNT REV ...

  • Tiny
  • jmbeam59
  • 1996 Toyota T-100
  • 189,000 miles

My truck was running rough and wouldnt rev higher than 2900rpm. Then it wouldnt start at all.

I cleaned the MAS
Replaced spark plugs
Checked relay behind glove box(works good)
Replaced fuel filter
Cleaned Throttle body
Replaced Fuel pump

Still nothing!

Fuel is getting to the rail however I don't have a fuel pressure gauge. Well I have one that said fuel and Vac gauge but it does not have any type of banjo fittings so Im not sure if this is the correct gauge to use.

Anyway When I spray carb cleaner in the throttle body the truck starts up. Before I replaced the spark plugs they were getting wet. I am stumped and dont know what else I should do. It looks like I wasted over $100 on a new fuel pump. WHat else could it be PLEASE. I need to sell this truck to get the last $4000 I need for spinal surgery or they will postpone the surgery. Like getting $38,000 already is not enough!

Thanks again

Sunday, October 28th, 2012 AT 1:42 AM

9 Answers

  • Tiny
  • ASEMaster6371
  • Expert
  • 25,502 posts

Stop spending money without making sure parts are bad.

From your description, it is either no fuel pressure from a power supply issue or a clogged cat converter not allowing the engine to breathe.

Roy

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Sunday, October 28th, 2012 AT 1:53 AM
  • Tiny
  • jmbeam59
  • Member

If the cat converter was clogged then the engine would not have started with the carb cleaner right? So I presume that is not the issue. Can you be more specific on your hypothesis? All relays and fuses seem to be good. I took the fuses out and tested them to make sure they were good. What else can I do to make sure the injectors are energized properly? Thanks

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Monday, October 29th, 2012 AT 7:16 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

Starting with carb cleaner indicates the problem should be fuel related and it could be low fuel pressure due to a faulty fuel pressure regulator, fuel pump, injectors or the PCM.

To test the fuel injectors for pulsing, you would need a noid light. Disconnect a fuel injector coupler and attach a noid light across the 2 terminals and crank. Ensure one of it has battery voltage when ignition switch is turned on. While cranking ngine, if the noid light pulses, that would mean the circuit is good. If it does not pulse, the problem could be with the PCM.

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Wednesday, October 31st, 2012 AT 10:13 PM
  • Tiny
  • jmbeam59
  • Member

Got the Noid light and injectors are good. PCM was alos tested and also I swapped one out of my other T100 with same engine and nothing. What next> ?

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Wednesday, October 31st, 2012 AT 10:23 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

You have not tested the fuel pressure so that should be the one to do now. One simple test is to pinch the return hose at fuel pressure regulator and crank to see if it starts.

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Wednesday, October 31st, 2012 AT 10:28 PM
  • Tiny
  • jmbeam59
  • Member

Sorry yes the fuel pressure was within limits.

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Wednesday, October 31st, 2012 AT 10:45 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

You tested the injectors for proper operations but did you test them for excessive delivery of fuel?

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Thursday, November 1st, 2012 AT 5:39 PM
  • Tiny
  • jmbeam59
  • Member

Tested them in every way, all fine.

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Thursday, November 1st, 2012 AT 6:19 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,939 posts

You have sparks, compression and fuel and engine is not starting. It works with starting fluid, that can only mean the fuel injectors are not working as required. Something must be wrong somewhere with tests carried out.

Revise through your test and see what went wrong. When all things fails, I always go back to the basics.

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Thursday, November 1st, 2012 AT 7:33 PM

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