87 R10 305 bogging down

[gmhammes]

So I pulled my fuel injected 87 r10 305 out of the garage this year after sitting for 10 years. (ran great before storing) Changed fluids, plugs, drained gas tank, put new fuel pump and sending unit in and she fired right up.
Went to take it down the road yesterday and it seems to choke or bog down when i accelerate but is fine at idle and does not die at all.
I've seen people throw a lot of parts at this issue with little luck and was hoping to avoid doing that. My mechanical skill level is high however do not own a lot of diagnostic tools.

Any thoughts or common issues that you know of with these?

Thanks

[mrolds88]

Did you change the fuel filter?

[gmhammes]

Yes, forgot to mention the new fuel filter. I'm reading a lot of threads today but still wanted to see if anyone has and quick test or fix for the issue. Since it ran fine before storage i assume it age related but don't know where to start.

[pontgta]

i would check fuel pressure... How did you drain the fuel?... only reason for asking is... are all the hoses connected back right?

[gmhammes]

So i've read to check fuel pressure before the filter correct? I can't see how i would get my pressure connector at the TBI. I pulled the tank down and drain the fuel that way. put about 5 gallons of fresh fuel in with some heet and fired it up. I am 95% positive the hoses are connected back right. It's been a month or so since i did that though.

[pontgta]

i am unsure about before the fuel filter, but the closer you get to the engine would be better i think. For these trucks very low pressure will do it. I hooked up the hoses wrong before....the truck idled right, but then when accelerated, the truck would die.

[gmhammes]

I know that if i push the throttle while in park it does not bog down. only when i had it in drive.

[gmhammes]

scratch the above post. Went home today and fired it up cuts out when the throttle is punched in park as well. if i gradually accelerate it seems to be fine but chokes when pressed hard.

[gmachinz]

If I had to take a guess based on personal experience, I would say if that 305 has over 100,000 miles I would suspect the timing chain/gears are worn pretty good. A worn timing set can cause you to replace everything timing/fuel related but often, a worn timing set is at least 75% of all "running" issues once you get well over 100K miles. I would suggest pulling the pan and timing cover to inspect for chain slop. Good thing is you have a 1-piece rear main and the pan can be dropped with motor still in truck.....so, plan for a good day to do it. Since your motor is ecm controlled as far as timing goes, you may not be able to "read" the balancer with a light to see if the timing mark walks around a lot....this is a method I use on older motors to gauge how well the timing set keeps time at a steady RPM.

[gmhammes]

Thanks for the advice. truck only has 83k on it but it won't hurt to check/replace the chain. I'll post back what i find out.

[gmachinz]

Cool....just remember under a load the timing chain is under more stress than at idle. If you find you have a miss/stumble at idle and a near fall on its face at WOT or near it, then I would be suspect of the timing set. The ecm if I remember correct on an OBD1 can only advance the timing 26-28 degrees or so....and if the timing slop gets further out of wack than that, the ecm just can't control spark further than that.

[mrolds88]

Originally Posted by gmhammes

So i've read to check fuel pressure before the filter correct? I can't see how i would get my pressure connector at the TBI.

Here's an item that you would use. Simply unscrew the pressure line from the back of the TBI and screw this on. Add a pressure gauge and you are ready.

http://www.ebay.com/itm/TBI-Throttle...e22a77&vxp=mtr

[gmhammes]

Thanx. Ill pick one of those up.

[gmhammes]

Another thing i noticed is my oil pressure maxed out at 60 even at idle. Thoughts?

[doubleclucker]

After sitting 10 years my guess would be the injectors are not flowing perfectly due to crud and rust dried tarnish on screens etc.
Take a look at spray while moving throttle.

[gmhammes]

Doubleclucker - i did that last night. as far as i can see they are spraying fine however i think i will throw a video up later today to get yours and others opinion.

[gmhammes]

Mrolds88-
Went ahead and ordered the actron fuel pressure adapter and gauge. should be here in a couple days and will hopefully know more this weekend with regards to fuel pressure that is.

[pontgta]

Dual fuel tanks? Make sure the hose inside the tank from the pump is clamped good and in good shape... I have had several that just deteriorate.

[gmhammes]

Yes however neither pumps were working when i pulled it out of storage so i went ahead and replaced the passenger pump and sender. The hoses are old however i didn't see any cracks. I plan on doing a fuel pressure test this weekend. That should tell me if the problem is fuel before the tb, correct?

[gmhammes]

Originally Posted by pontgta

i would check fuel pressure... How did you drain the fuel?... only reason for asking is... are all the hoses connected back right?

What should me fuel pressure readings be at the tb? Plan to test it tonight if i have time.

[LONGHAIR]

I would look into the fuel injectors. This is the most likely reason for stumbles/bogs.
That is not to say that there are not other issues, but throttle opening bogs are air-fuel related most of the time.

[gmhammes]

If there a less expensive way to tell if it is the injectors rather than replacing them?

[pontgta]

Originally Posted by gmhammes

If there a less expensive way to tell if it is the injectors rather than replacing them?

Check out this video... I have heard. That you can visually see the injectors spray, but I have not done this my self.



http://youtu.be/pyz5qx0N6Sk

[gmhammes]

Thanks. didn't do anything over the weekend with the truck as it was pretty cold here and had a family event to attend.
Will hopefully return to diagnosing this week. First test is fuel pressure and to look at the injector spray.

[gmhammes]

UPDATE - so i checked the fuel pressure last night and it while at idle it was at 14 or so. With regards to the injectors, they seem to be spraying fine but again, i will try to get a video up tonight.
Any more suggestions. I don't think it the temp sensor and it IAC simply because from what i've read most of thos issues occur at idle which my truck runs fine at idle just bogs down when the trottle is punched.
I hate to even mention it becuase i don't have much experience with adjusting it but i'm thinking it may be a timing issue.
Any other thoughts, please?