raw gas coming form tailpipe
05-20-2012 | 02:07 AM
#16
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Seasoned Member
Joined: Jan 2011
Posts: 474
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From: brandenburg ky
Year: 1990
Model: Cherokee
Engine: I6
If those are the stock injectors, allot of guys can those and go to the four hole design even if they happen to be working right.
Checked your MAP tube? There is a little tube from the inside of the TB, back, up to the MAP there on the firewall. Off, cracked or plugged and the MAP will tell your ECU you have your foot in it.
I really doubt that's gas. I'd put a tiny bit on a stick or a rolled up piece of paper and see it it lights if I wasn't sure.
Gas vapor needs to be within a certain range to explode. Too rich and it actually won't go bang! (36%?).
Checked your MAP tube? There is a little tube from the inside of the TB, back, up to the MAP there on the firewall. Off, cracked or plugged and the MAP will tell your ECU you have your foot in it.
I really doubt that's gas. I'd put a tiny bit on a stick or a rolled up piece of paper and see it it lights if I wasn't sure.
Gas vapor needs to be within a certain range to explode. Too rich and it actually won't go bang! (36%?).
05-20-2012 | 10:12 AM
#17
CF Veteran
Joined: Aug 2011
Posts: 10,489
Likes: 19
From: Nor-Cal Coast
Year: 90,84
Model: Cherokee
Engine: 4.0,2.5
Ok...Just that that MAP tube is so small and brittle. The way is snakes along the manifold then through to get up to the map allot of guys miss it, if that has a little crack. You can pull the fitting right off the MAP and feel with your finger.......
If I had a Renix Jeep here and I wanted to fix it, the first thing I would do is take two minutes and check it's hart beat.
AC voltage CPS test; Small clips on the meter leads really helps.
Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps.
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if your battery is low)
Mine somehow works with only .3 my wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8. **Update, it soon failed. I installed Napa #css980 in my 90.**
If it's low you can modify the cps. With the next largest bit that won't fit in the hole, enlarge the hole's in the bracket just a tad. Now when mounting it's crucial to maintain firm downward pressure on it while tightening the bolts. An assistant could help with that from above.
Then I would check for vacuum leaks.
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep.
If I had a Renix Jeep here and I wanted to fix it, the first thing I would do is take two minutes and check it's hart beat.
AC voltage CPS test; Small clips on the meter leads really helps.
Unplug the connector at the back of the manifold with wires going down to the bell-housing/cps.
Probe the two wires to the cps with the meter set on AC volts. (a 200 scale on mine).
Crank the engine and note the voltage. (jump it if your battery is low)
Mine somehow works with only .3 my wiring/grounds must be pretty spiffy. .5 seems to be a good mark. One article talked of .5 to .8. **Update, it soon failed. I installed Napa #css980 in my 90.**
If it's low you can modify the cps. With the next largest bit that won't fit in the hole, enlarge the hole's in the bracket just a tad. Now when mounting it's crucial to maintain firm downward pressure on it while tightening the bolts. An assistant could help with that from above.
Then I would check for vacuum leaks.
Vacuum leaks suck. I go around with short little shots of starting fluid, if you hit one the sound of the engine will change. Small little shots! You don't want that stuff to accumulate. It's a fire hazard, but It evaporates right away. Also with a tube, or a section of hose you can listen for it. Don't forget the lower O rings on the injectors need to seal as well. (uppers would leak fuel).
The manifold bolts have a habit of loosening, especially that rear one. On anything like that you never want to tighten only one. It can warp/bend, even crack things. If I found that any that where easy to reach where loose, I'd pull the air cleaner and tighten them all, starting in the middle and working out towards the ends. I go over about three times. It's a bear of a spot to get a torque wrench on them all. Just don't ape on it. If its firm and not turning, no point in going on to break it, a REAL *****. The rearmost bolt underneath takes a little doing, but it can be done with the right extension. For that very back one by the firewall I use way long extensions (18"), with a swivel at the socket. Anyway, that's a good thing to check on any old Jeep.
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