xveganxcowboyx

Things didn't resolve as quickly as I had hoped. There was some bucking, diagnosing, wrenching, more bucking, and so on. I ended up putting one of my old injectors back in after a cleaning since one of the new ones leaked. I'm pretty much back to square one. I'm darn tempted to replace the fuel pump since there isn't much else that I can think of. The plugs are pretty black though, which seems to indicate it's getting plenty of fuel. I haven't replaced the coil yet so that could be an issue. Sometimes I can give it 30-40% throttle and it goes pretty well. Particularly in first gear with less load. Sometimes it sputters at pretty much anything over idle.

cruiser54

That connector is a pain at the MAP.

DFlintstone

First..a 746 leaked? Are you sure it was not the upper O ring? A solid cast injector shouldn't leak.

Wonder if you got a bad MAP, do you still have the other one? (seems easy enough to try. Their are "static" tests for the map, with a DVM. (dig. meter), Then a "dynamic" test, with an old style analogue meter. (or I guess a spendy digital). You actually need a vacuum pump....you watch the needle smoothly sweep as vacuum is applied.

Check out this link, it has the procedure for the easy MAP check>

http://www.lunghd.com/Tech_Articles/...iagnostics.htm Make sure terminal A has less than an ohm to bat. neg.

Also a while back, a guy here CPTslackass I think had a real booger. His would only work with his CTS under the manifolds unplugged. He tried like three of them, then later IIRC found that mice had chewed his wiring. Granted this sounds a little goofy, but maybe try unplugging both that and the IAT and see if that helps. (after ruling out the MAP)

xveganxcowboyx

It leaked from the nozzle rather than the body. I pulled the plugs and all matched except number 3 which was pretty clean and wet with fuel. When I tested it with carb spray and low pressure it would spray/leak when voltage wasn't being applied.

I still have both maps. In fact the new one is plugged in currently, but the original is still attached to the firewall so switching between the two is easy enough. I checked resistance on the original and that was fine, but I will try the vacuum test.

I'll disconnect those sensors and see if anything changes. In the very least that will simplify things. I don't know about mice, but the is some level of corrosion on lower components due to water/mud exposure so it is possible there is poor contact being made. Time for cleaning and dialectic grease.

MetalVamp26

xveganxcowboyx

That could definitely be the problem. I would disconnect the fuel rail, fix the lines so that you can install fuel filter (or disconnect line to tank) and use compressed air to blow out the fuel lines from front to back. Then spray carb cleaner into fuel line (a lot) then repeat air flush.
If you wish to replace the injectors I would go with the 4 hole Bosch tip design (if they will fit your application). Talk to Jim at Injector Repair LLC. Great guy. Just spent an hour talking to him. If he does not have the correct injector for your app, he will give you the exact part number for the exact flow rate you need. I learned a ton talking to him.
http://injectorrepair.com/
Many people are selling refurbished injectors but do not have the exact flow rate needed. Stock, mine are 19 lb. Many people are selling 17 lb, and saying that the 4 hole design gives the same volume in mL of fuel. not true from what Jim said. He has tested OEM next to all of the Bosch ones and found out which have the exact numbers.
Good luck on your project and hope that this info may help you and some other jeepers out there.

xveganxcowboyx

Well not I get to look stupid publicly. There was one suggestion early on, which was reiterated again, and I waited to check. Bad fuel. I figured since the tank was shiny and new, the old fuel pump was sitting in the back of the truck, and it ran great when I first drove it that couldn't be an issue. Further, I pumped out the tank and put fresh gas in it and still had issues.

The explanation seems to be: the tank was changed, then left with 3-4 gallons of fuel in it for god knows how long, which coated the inside with a lot of varnish. This wasn't a big deal until I added a bottle of Chevron with Techron cleaner. Doing it's usual great job it broke the varnish loose and turned any fuel in the tank in to yellow soup.

I dropped the tank, dumped a bunch of solvent and some nuts and bolts in, shook it until it was clean, and now it runs great. It's the first time I've gotten to hear the Mopar exhaust at full throttle and it sounds great! Now on to fixing the death wobble and leaky transmission output seal......

cruiser54

Is your fuel filter gonna get clogged by nuts and bolts next?

Great job BTW!

xveganxcowboyx

They don't shake out easily so I almost left a few in. Then I thought about how crazy the clanking sound would drive me. Magnets can be so handy.

I also took the opportunity to add some high density foam on top of the fuel tank. The Jeep is gutted and the ballast resistor is bypassed so the fuel pump was really loud. It's quiet(ish) now.

DFlintstone

INTERESTING! I was having a long crank time occasionally. But before I figured out weather I was loosing fuel pressure from an injector, or the check valve, I filled up with Chevron premium, (for the Techron), before a smog check. Guess what? Not only did I pass with better numbers than 2011, but the long crank went away.

Went between Dec. 8 and March 3, 1,833 miles, with it loosing pressure. During the second tank of the Chevron is when I noticed no more long cranks.

Glad for your success, and much thanks for getting back. At least a couple of guys with your symptoms just faded away with no solution. Now we all know more!

xveganxcowboyx

No problem. I hate finding threads with exactly my symptoms with just a post at the end saying "I figured it out."

I am a fan of the bottled Chevron cleaner. Techron is just a brand name for polyetheramines which are by far the best cleaning agents for gasoline. Most cleaners have little or none. I think Redline has some and Gumout "with Regaine." Any top tier gas stations should have decent amounts added for maintenance. Adding cleaners is generally only necessary for neglected vehicles. This is the first time I have had cleaning actually make things worse since there was so much gunk to break up. It was too good at it's job, lol.


*edit* My long crank time hasn't gone away, but has diminished a fair bit. I'm sure it will take a while to fully clean out the gunk from the old lines in this truck. I'm also sure having gas that actually combusts helps as well.

cruiser54

Try BG44K if you really want to see an improvement.

also keep in mind that a REnix will always crank a bit.

DFlintstone

X2, Renix jeeps always crank a bit. They don't need the cam sensor, but with it the ECU can register a rev, and that it got to 300 rpm fast enough. Without the cam sensor it might take longer for the ECU to figure out a rev happened.

I might know somebody, who knows somebody to get BG44K. Cash only...call me "Barny".

"I'm also sure having gas that actually combusts helps as well" YES! Your research coincides with mine! The burning kind works better!