random spudder and dies restarts after a few mins

[broncobuckinaround]

86 b2 2.9 auto

either going up hill on a long drive through the mountains or four wheeling through some mountain trails.

many new parts. fuel pumps and filter. new reman distributor and ecm. rebuilt 6000 miles ago. havnt replaced any sensors cept oil pressure sending switch.

some oth er problems it has is a long crank time before it starts. it has new plugs and wires. and fuel pressure is where it should be.

i assume its going to be a sensor or maybe an old connector needs to be replaced. just dont know which one. need some ideas on where to look. thx guys

 

[RonD]

I would spray some starting fluid into the intake and then try to start, if it fires right up then you still have a fuel issue if it still doesn't fire up right away then spark would be the issue

First place I would start would be the TFI system:
http://www.therangerstation.com/tech_library/TFI_Diagnostic.html
download and print the work sheet

Long cranking time wouldn't fit O2 sensors, they are not used until engine is warmed up or for at least 2 minutes after starting hot.

ECT sensor(2 wire near t-stat housing) would only cause hard starting cold or hot but not both.

MAP sensor(on the firewall) could be a problem but engine should still fire up quickly just not run well.

IAC sensor(idle air control) might cause an issue at startup and idle but not while driving.

Do you have an EGR system?

 

[broncobuckinaround]

i will do the starting fluid trick to see what happens.

i do have an egr but havnt got a clue if it working correctly or not.

it could be the ects. last i check it was a dark color not nice and brass colored. i did however use 3000 grit sand paper the make clean looking. probably didnt make any difference but i did it. lol.

map works. found that out cuz the hose got loose and it was running funny.

im am cautious about the iac because if it starts to fail it will make the engine do weird things. shutter and die. but when it does it i hold the throttle wide open and it still dies. it should be replace anyways. because it think the pintle is getting weak.

 

[Dune Runner]

Weak coil. I had a car run like that years ago. Drove me nuts for months. A new coil cured it. Just an idea.

 

[broncobuckinaround]

thx dune runner, much appreciated. but ive already done the coil. it had a weak spark, orange spark coming from it so i replaced it with msd coil. it was like hi im a super spark, kinda like the one where you tell dumbass friend to touch and crank the motor. watch the guy freak out. lol. yup done that plenty of times. and people wonder why i only have friends that know stuff about cars

anyways i just found that my gas tank vent was plugged up with crystalized gas. so i took it apart carefully after i found that nothing could get past it. so with that said i removed the plug/clog. and put all back together.

ill find out tommorow if it works or not. it could also be my issue with the long crank time. cuz maybe the fumes help with the starting. lol i havent got a clue but i like to think i do. lmao.

 

[RonD]

Yes, closed gas tank could build up negative pressure and slow flow to injectors, but that would take time.
Have you noticed a louder suction when opening the gas cap?
And you can always just loosen the gas cap to test if tank pressure is an issue.

The EGR valve will have a vacuum line on the top, remove it and plug that hose.
Put another hose on the EGR valve.
Start engine
While engine is idling suck on that new hose, EGR valve should open and engine will run rough and maybe stall if you hold it open long enough.
Stop sucking and idle should return to normal, if it doesn't or sucking has no effect then EGR valve needs to be cleaned or replaced.

The EGR does three things, it cools the cylinders when they are under load, it prevents pinging while under load, and it lowers emissions.
EGR valve should only open when engine is at higher RPMs and under load.

 

[broncobuckinaround]

the gas tank never did suck in air it allways pushed it out. but since i cleaned the vent it doesnt do anything just acts like normal.

i will check the egr and write down the results. thx ron