crank no start have spark+fuel+compression

[flatblackford92]

hey yall. I have a 1994 x with a pushrod 4.0. bought it not running. changed fuel pump, plugs wires, crank pos sensor, tested for spark, has spark, tested with fuel gage 38# at the fuel rail. if I pull the plugs theyre bone dry. im thinking for some reason, the injectors may not be firing. im trying to eliminate causes one by one. im thinking its either the cam pos sensor, or the pcm. CMP sensor has 11 volts at the connector. im not quit sure what the problem is. is thdre a way I can test them before I spend $150+ on a CMP sensor and pull the intake to change it, without really knowin if thatll fix the problem and get t to start? any thoughts or input would really be appreciated

 

[natenkiki2004]

Since you bought it as not running, how long did it sit? Could be the injectors dried and crusted up internally.

Disconnect the intake tube at the air box and have someone crank it while you shoot starting fluid in. If it catches, fuel is very likely your problem and you might think about getting new injectors.

 

[MrShorty]

Along the same lines, you can hook up a "noid light" or oscilloscope to the injectors and see if they are being fired electrically. If they are "firing" but not opening, then I would second removing the injectors and replacing them if they cannot be cleaned up.

 

[flatblackford92]

yeah well I already know it starts on ether, that I tried before I even bought it. but originally, I checked the fuel pump relay and inertia switch, both of which were ok, but te fuel pump wouldnt , so I replaced that with no success. I know the fuel injectors arent firing, im just wondering if its the injectors themselves, or the cmp sensor since it sends a signal to the pcm to fire the injectors. im trying to borrow a noid light from a friend of mine, im just wondering, if the noid light does verify injector pulse, then would I be correct in assuming that most likely the injectors are either clogged, or defective, or is there any other potential issues it could be that im overlooking? thanks for the replies

 

[natenkiki2004]

If it sat for a long time and the fuel leaked/evaporated/disappeared from the injectors, it's likely they're varnished/gunked/frozen. They're meant to be wet for lubrication and cooling, just like the fuel pump.

If the noid light verifies that they're being triggered, I would personally replace them all anyway with a reconditioned set. Even if you did get them to work, you'd likely have poor performance, MPG or even a dead cylinder or two at worst. $125 and you're on your way with a good & clean spray.

If you don't end up getting the noid light, a stethoscope or rod/screwdriver would work, you should hear them all click. They're loud enough that if you listen carefully, you can hear them with the engine running without any tools.

Something free you might try, I don't know the computer intimately but with some sensors disconnected, there's default values that the engine uses. Crankshaft position sensor and MAF are absolutely critical but I think most all the rest can be disconnected to help troubleshoot where an issue might be. The early Explorers didn't have camshaft position sensors. If it's not miserable to get to, I'd unplug that and see what happens... it's free.

 

[flatblackford92]

the truck had sat for probably a year, and the pump wS in horrible shape, rotted out, and the gas o drained from the tank was dirty as hell, looked like oil. so I blew out all the fuel lines, replaced the pump and sender, the whole assembly, and the fuel filter. I just picked.up a noid light set today, and im gonna go out there now and play around and see what I get. I am gonna try to clean the imjectors and at least sed if itll run at all. ive put more $ in parts in already than I paid for the whole truck. does anyone know what # injectors these trucks come with stock? 19?

 

[natenkiki2004]

These are what you'd need:
http://www.ebay.com/itm/300499569879?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

If the link dies, search Google/eBay for:
"Bosch Fuel Injector 4.0L Ford Explorer Ranger Mazda B4000 0280150931 92TF-AA"
Motor Man Injectors

 

[flatblackford92]

yeah I know I was already looking at some injectors. I pulled them out yesterday, and three of em were really bad, gunked up, so I already ordered a set of remanufactured bosch injectors from cs performance for 108 free shipping on ebay. I was thinking about replacing the electrical top piece of the cam position sensor while I have the upper intake off. its 25 bucks on ebay, and id just hate to put it all back together and it not run because of that sensor. I dont see how the bottom part of it could really go bad, and when I checked the connector for it while cranking the motor over, it seems theres power going to it, but not coming back out from it. I think ill order the injectors, and that top piece just for piece of mind. I still have to clean out the holes in the lower intake where the injector sits in. theyre pretty dirty too. I just want to make sure everything is ok down there, cuz if I put it togetger and it still dont run, im out of ideas and almost out of patience lol. thanks again for your time and your input brother, I appreciate it. ill let ya know how it goes

 

[natenkiki2004]

Take your time with those injector holes. I used loads of q-tips and wiped with them in a twisting motion, careful not to knock any crud into the intake. When you get the injectors, install them asap. Use some lubricant on the o-rings and they'll pop right into place. I chose 2-cycle oil as the lubricant since it will quickly wash away with gas and not hurt the engine.

I'd also go for that sensor but do be warned, cheap ones will yield cheap results. A lot of people go Motorcraft on those kinds of parts but a cheap one should at least give you an idea.

*EDIT*
I'm leary of the injectors you see for $108 from CS Performance. The only kit I see for the Ford 4.0 is $145. Make sure you get the right ones.