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Howdy all,
I've got a wimpy 302 in an '87 van. I'm getting plenty of fuel to the motor, but it acts weak until I give it full throttle. I tried the filter and regulator to no avail. I'm wondering about the injector seals now. Can I use carb cleaner at the spot where they go into the manifold and see if there's an RPM increase? That trick used to work on the carbed engines from my recollection. If that isn't going to work, is there a better way of checking the seals with out pulling the thing apart, at least until Spring.
I've checked the archives and didn't find an answer. I also wonder about the TPS, but I've got the Helms '87 emission/diagnosis manual for help in checking that out.
Any help would be greatly appiciated!
-John R.
Yes, you can spray around the injectors. They ususally don't suck air there, but it is possible.
I would check the TPS. First check the output voltage at an idle. It should be no more than .99 volts. Then, use an ohm meter to see if the resistance changes as it is opened. Do it slowly so you can check for an open spot at the same time.
Also, recheck the timing to make sure that it isn't too low. It should be at 10 Deg BTDC with the spout plug removed.
Jimmy
I hope to check the TPS out in the next day or so. It'd be nice for the thing to have a bit more power at something less than full throttle. The hesitation is getting old too!
-John R.
I think your saying that it isn't idling well, I imagine it rev's low at idle and dies at idle? Check your plugs, wires, dist cap and rotor (make sure the terminals haven't been eaten up from arcing and sparking) always use dielectric grease on wires and plugs to prevent damage from arcing. Definetly check your compression! bad compression will always screw up idle, Compression testor is only 20 bucks. Make sure there are no broken or leaky vacuum lines. The vacuum lines are more important than we realize, the vacuum helps control important emissions systems. Of course there is the ignition timing, running a timing light to spot the marks is a good idea, but there are many things that could screw up the timing. Bad harmonic balancer, worn gears, timing belt/chain, distributor malfunction, etc.
I hope your 302 isn't a lemon, I had an 87 stang with a 302 HO, and that thing had alot of issues when it was cold and idling, the most common problem being surging at idle.
I fixed the problem by cleaning the throttle body and butterfly air inlet, and replaced throttle body to intake plenum manifold gasket
I ran the codes on the thing. I got two. A 63 (TP circut below minimum voltage) and a 98 (not sure, but I believe it has something to to with a test failure). The OTC gauge siad to fix hard faults, then rerun KOER test. I'll fix the TPS and see where that gets me. From the looks of it' i'll have to pull the throttle body to get at it. This van ain't gonna be as easy as my F150 w/I6.
-John R.
That 98 means that there is something way wrong with something that the computer needs to operate. It could be several things, so many that the computer cannot run the truck properly. I would check all wiring before you start replacing things.
As it stands now there's not much I can do. Christmas is expensive when you've got kids!
I imagine from the way it's running, the TPS is in need of replacing or adjusting. From what I understand,it can be adjusted radially to get the desired volt value. It may be putting nothing out and that's why the test couldn't be completed. I know that from running the same tests on my '90, it kicks up the RPM during the test.
It looks as though the throttle body will need partially removed to access the two phillips screws. I've got to replace the clutch master cylinder on my F150 first. I can't have two down Fords!
I know what I want for Christmas. A gift cetificate to a parts store!I will run wires though. If nothing else, it'll get me out of the house for a while and escape the battery operated toys with lights and noise.
Thanks for the input, and have a Merry Christmas EPNCSU2006
-John R.
Thanks John, I know the feeling. I'm hoping to get my truck running right over the holidays as well. Good luck with them and have a Merry Christmas too.
You'll have to take off the throttle body to get to the tps, but you won't have to disconnect everything from the throttle body. You can leave the IAC, and the coolant hoses attached, and it will rotate enough when you take out the 4 bolts attaching it to the manifold, to get to the tps. I also had to drill out one of the holes in the tps to be able to rotate it. Good luck.
Thanks for the well wishes. I reckon I'll need 'em! The only thing that looked to make me nervous is the plastic things on the ends of the throttle linkage and shift linkage to the tranny. I'm great at screwing those up. Are there any good ways to disconnect them if need be?
For today, I'll try to at least see that the TPS is even getting power. I got a brand new multimeter to try out.
-John R.
Do they snap off? Well are they supposed to snap off (haha)?
Like I kinda hinted at, I've got a gift a screwing up the simple. The tricky stuff never seems to mess with me as much. Such is luck, at least it normally the cheap stuff for me.
-John R.
They usually snap on and off. Over the years though, the plastic gets brittle and eventually, they crack and fall apart.
It seems that the TV cable inserts on the Crown Vic's that is in the throttlebody linkage are the worst for breaking. This will kill an AOD tranny quick when driving without the cable hooked up.
Jimmy
Oh yeah, you could always spray a little WD-40 on them before removing the linkage. It make keep them from breaking.