87 Renix XJ with irritating intermittent miss
Thread Starter
Junior Member
Joined: Aug 2012
Posts: 33
Likes: 0
From: Tucson, AZ
Year: 1987
Model: Cherokee
Engine: 4.0
Idk what Napa has. I want 19#, 4 hole injectors in any case. I don't plan on changing my FPR.
Since I average out around 14, "knocking around" with my 703's, (with at least some highway) it must be really sucking just knocking around. I DO get 18 or better on highway trips when the 02 sensor is trimming the mix. (closed loop). "shoot low, theyre riden Shetlans" is not an injector selection strategy. I'm aiming for the correct match this time myself. Google or Ebay 19# Ford Yellows. Heck, if three of us bought set's of 8, we'd have four sets of six 180/4 = $45 a set...for what seems the correct part.
I do have 8, 703's, six in use. They might be 23lbs/hr. Just within "closed loop" parameters. Idles, runs great!
I've just had the same high idle deal btw. Was on the highway...but yea, it went back after turning it off.
Like I mentioned in post #2, a couple bottles of alcohol might be in order, (or one 32 oz bottle). Oh, and some in the Jeep too.
You CAN just stick the 703's right in there. Same connector and fuel pressure. It will feel and run great. I'd make you a deal on mine if I had some #19 Lb in my hand!
Since I average out around 14, "knocking around" with my 703's, (with at least some highway) it must be really sucking just knocking around. I DO get 18 or better on highway trips when the 02 sensor is trimming the mix. (closed loop). "shoot low, theyre riden Shetlans" is not an injector selection strategy. I'm aiming for the correct match this time myself. Google or Ebay 19# Ford Yellows. Heck, if three of us bought set's of 8, we'd have four sets of six 180/4 = $45 a set...for what seems the correct part.
I do have 8, 703's, six in use. They might be 23lbs/hr. Just within "closed loop" parameters. Idles, runs great!
I've just had the same high idle deal btw. Was on the highway...but yea, it went back after turning it off.
Like I mentioned in post #2, a couple bottles of alcohol might be in order, (or one 32 oz bottle). Oh, and some in the Jeep too.
You CAN just stick the 703's right in there. Same connector and fuel pressure. It will feel and run great. I'd make you a deal on mine if I had some #19 Lb in my hand!
Last edited by holeshot9g; Feb 11, 2013 at 01:14 AM. Reason: add more info
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
Likes: 1,579
From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
If the wires were there and unplugged, your Jeep wouldn't run at all.
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Funny! That's twice I turned on my computer minutes after you posted...Anyway I believe it's Bosch # 280 155 700. If you google/Ebay things like "19# ford yellows" that is what comes up...often. It WOULD be nice to hear from somebody else though. I think those are the correct length, with the correct plug and play EV1 connectors, and 4 holes. In the Ebay listings you will see lots of "applications" for them. Trucks, vans, Mustangs, all sorts...pages of them. Myself I'd go for used from the JY to maybe save a buck, but vendors here, (and Ebay sellers), might have cleaned/checked them, even "flow matched", where they test and group injectors that flow about the same. I guess there are slight variances with the same part. I trust Napa as well but they might be pretty spendy compared to used ones.
How is your miss? Your pump noise changing might be a clue, IDK. Rubbing alcohol is cheap!
Oh, and, it idles, runs great with the 280 155 703's. Lots of guys here run and love them. I might be getting 5 MPG less, (or worse) on short errands...moving a trailer or yarding a log, then I do, usually pretty well loaded with tools and junk on the highway. I'm pretty sure the 19# will dump less fuel while it's cold than the 22#. What that actually works out to in real MPG, I can't say...yet!
How is your miss? Your pump noise changing might be a clue, IDK. Rubbing alcohol is cheap!
Oh, and, it idles, runs great with the 280 155 703's. Lots of guys here run and love them. I might be getting 5 MPG less, (or worse) on short errands...moving a trailer or yarding a log, then I do, usually pretty well loaded with tools and junk on the highway. I'm pretty sure the 19# will dump less fuel while it's cold than the 22#. What that actually works out to in real MPG, I can't say...yet!
Last edited by DFlintstone; Feb 11, 2013 at 05:39 PM.
Newbie
Joined: Jul 2012
Posts: 6
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From: Fort Carson, Colorado
Year: 1990
Model: Cherokee
Engine: Renix 4.0 i6
I had that exact same miss you are talking about on my1990 renix xj. It would skip really bad when cold than would run fine for a while when warm, and get really bad at stop lights never did die out just sounded like it had kind of a hiccup. After searching everywhere for someone with the same problem and replacing and cleaning damn near everything, I decided to replace the injectors. I found a set of 8 rebuilt 19# four hole EV1 ford yellow top injectors for 99 bucks on E bay. It took all of about an hour an a half to do the swap and holy cow best 100 bucks I have spent on that jeep. After running around for about a year with that super annoying miss it was finally running perfect. It even feels like I gained a little power, not much but noticeable. Throttle response is instant and it just feels like a whole different jeep now.
Newbie
Joined: Jul 2012
Posts: 6
Likes: 0
From: Fort Carson, Colorado
Year: 1990
Model: Cherokee
Engine: Renix 4.0 i6
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Newbie
Joined: Jul 2012
Posts: 6
Likes: 0
From: Fort Carson, Colorado
Year: 1990
Model: Cherokee
Engine: Renix 4.0 i6
Boy, got me...this shows here at a pretty high rate, but leaves out at what pressure.
http://www.fuelinjector.citymaker.co...low_Rates.html
I guess it might get pretty technical with different voltage and pressure. Idk...lots are rated at "3 bar" , maybe that's 43 lbs....checking....(learning)
How's your mileage?
http://www.fuelinjector.citymaker.co...low_Rates.html
I guess it might get pretty technical with different voltage and pressure. Idk...lots are rated at "3 bar" , maybe that's 43 lbs....checking....(learning)
How's your mileage?
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 24
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
I'm just looking at 87-90 Renix. Anyone interested in injectors might like this link. It shows the 280 150 943 at 18.25 Lbs at 3 bars. Just fine I suppose. No idea if with a stroker or for high performance if you might want a higher rate. Because the 280 155 700 has no seam I might prefer to go that way. I don't know of ANY problem with the two piece, just my stock Simmons Decca? leaked there. I'm just looking at 87-90 Renix Jeeps.
AW Crap! This has the 280 155 703's at 16.75 lbs..Wrong! (I think)

http://users.erols.com/srweiss/tableifc.htm
This one below might be better. I'm pretty sure the above has at least one incorrect stat. (on our 703's). Bosch themselves....I can't seem to find anything from them other than buying new..
http://www.fuelinjector.citymaker.co...low_Rates.html
Cool! Agreed mighty8. I see people like them, and looks right to me. Yea, with the 4 hole 703's I felt a great improvement with the idle and throttle response. Good closed loop highway mileage as well. Since I should be able to sell my 703's for about what 700's might cost, someday I'll see if I can pick up a few "knocking around" mpg's. (sounds like you are set at 18-1/4 Lbs, in "default", cold. Thanks!
AW Crap! This has the 280 155 703's at 16.75 lbs..Wrong! (I think)


http://users.erols.com/srweiss/tableifc.htm
This one below might be better. I'm pretty sure the above has at least one incorrect stat. (on our 703's). Bosch themselves....I can't seem to find anything from them other than buying new..
http://www.fuelinjector.citymaker.co...low_Rates.html
Cool! Agreed mighty8. I see people like them, and looks right to me. Yea, with the 4 hole 703's I felt a great improvement with the idle and throttle response. Good closed loop highway mileage as well. Since I should be able to sell my 703's for about what 700's might cost, someday I'll see if I can pick up a few "knocking around" mpg's. (sounds like you are set at 18-1/4 Lbs, in "default", cold. Thanks!
Last edited by DFlintstone; Feb 11, 2013 at 10:29 PM. Reason: 16.75 lbs




