Newbie Fuel Injector change

Lanthanaas · Aug 22, 2014

Hey I'm very new to engines and I'm learning as I go. I've got a friend who has an 87 Jeep Cherokee that has been sitting for about 5 months. Their apartment was paving this week so it had to be moved. I tried to jump it with me truck, but as soon as it started cranking, gasoline started to seep out from the top end of 2 of the fuel injectors. We were able to pull 6 from a junkyard and all the O-rings are in good condition. That's where I think the failure was, although we have yet to pull his out. I've watched a few videos on Youtube as prep work, but I'm still a novice with most of the engine systems.

My questions are 1) should I do anything before, during, or after installing the injectors to make sure that the injection system performs correctly? 2) What sort of cleaning solution/process should I use on the injectors prior to installation? They are pretty much covered in dirty oil.

CompleteCherokee · Aug 22, 2014

I use carb cleaner on them and a lint-free rag. But be careful not to get any gunk into the cylinders. Also, make sure to lube the o-rings before installation.

ParadiseXJ · Aug 22, 2014

The stock 2 piece injectors will almost always leak eventually. I'd take this opportunity to upgrade to a Bosch or Bosch design one piece injector. They may or may not improve performance...but they will not leak, at least mine haven't, ever.

http://www.ebay.com/itm/Reman-4-Hol...es&fits=Make:Jeep&hash=item3a95c12cc4&vxp=mtr

ParadiseXJ · Aug 22, 2014

I just soaked the O-rings in fuel for 10 minutes and smeared a little Vaseline on them, get them all lined up on the fuel rail and the block, .they pop right in.

XJwonders · Aug 23, 2014

For a renix engine, u can use Volvo 746's injectors as an upgrade.

Lanthanaas · Aug 23, 2014

Unfortunately, we're working on a very limited budget, so I don't think upgrading will be an option. I'll keep that in mind for my 89, though.

Lanthanaas · Aug 23, 2014

What makes it a renix engine?

XJwonders · Aug 23, 2014

Renault/bendix engine management system. 87-90. Renix for short.

cruiser54 · Aug 25, 2014

Lanthanaas said:
Unfortunately, we're working on a very limited budget, so I don't think upgrading will be an option. I'll keep that in mind for my 89, though.

Under $100 for all 6 is too much for your budget?

Lanthanaas · Aug 25, 2014

Too much for his budget, yes. So far I've ended up buying everything for the project. We installed the "new" injectors yesterday. One of the o-rings tore while trying to get it into the fuel rail. We didn't realize it until we tried to crank it and it started leaking. New o-ring to be installed next weekend because it was getting late and the wives wanted to "see us" or something.

Lanthanaas · Aug 25, 2014

ParadiseXJ said:
The stock 2 piece injectors will almost always leak eventually. I'd take this opportunity to upgrade to a Bosch or Bosch design one piece injector. They may or may not improve performance...but they will not leak, at least mine haven't, ever.

Both the injectors we pulled from his vehicle and the ones we got from the Pick n Pull were a solid piece. Does that mean we don't need to worry about this?

cruiser54 · Aug 25, 2014

They "appear" to be a solid piece.......until they begin spraying fuel on the exhaust manifold.

CompleteCherokee · Aug 25, 2014

and with a leaking o-ring, don't fire it up until you have a replacement o-ring. No sense in burning it down, as I'm sure that would wipe out the rest of the budget

Lanthanaas · Aug 26, 2014

cruiser54 said:
They "appear" to be a solid piece.......until they begin spraying fuel on the exhaust manifold.

First off, what is the exhaust manifold? Is that the metal plate under the fuel rail?

Here are the injectors we got. Where is the seam on them?

Also, I saw a video where a guy pulled out filters from the injectors and replaced them. The person at the auto parts store didn't think they had built in filters. Is this something I should replace?

Lanthanaas · Aug 26, 2014

CompleteCherokee said:
and with a leaking o-ring, don't fire it up until you have a replacement o-ring. No sense in burning it down, as I'm sure that would wipe out the rest of the budget

LOL Explosions and fires are strictly forbidden!

cruiser54 · Aug 26, 2014

It's a crimp where two halves of the body come together.

CompleteCherokee · Aug 26, 2014

Lanthanaas said:
First off, what is the exhaust manifold? Is that the metal plate under the fuel rail?

The exhaust manifold is the 'tubing' that goes from the cylinder head and merges into a single pipe that connects to your exhaust system:

http://www.completecherokee.com/prod-303.htm

Lanthanaas · Sep 1, 2014

Alright, we finally got the injectors in. One of the o-rings tore when pushing it into the fuel rail. They came with the used injectors, but were in good condition, other than the one that tore. We replaced the torn one and tried to start it.

The o-ring between the fuel rail and the fuel pressure regulator gave out at that point. Luckily we had some of the new ones left. Got that replaced and tried jumping it again.

It turned over for about a second and then died. After that it wouldn't even turn over. It revs slowly like it doesn't quite have enough juice to get turning fast enough, even though it's hooked up to a good vehicle with jumper cables. Anyu suggestions what to try next?

CompleteCherokee · Sep 2, 2014

charge the battery overnight, verify it has 12v minimum, and then try starting again.

Hillbilly XJ · Sep 2, 2014

CompleteCherokee said:
charge the battery overnight, verify it has 12v minimum, and then try starting again.

12v is way too low need at least 13.8v or so at 12v its almost dead.

Newbie Fuel Injector change

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