jretzky

Well I'm back again.
Last week my Jeep ran great and two out of 5 week days it rained all day.


My Jeep sat all day Saturday and Sunday and this morning it started right up and on the way down the hill it fell on it's face.


It was running with no acceleration and back firing through the exhaust.


I have replaced the cap & rotor, plugs, and wires.


I looked through Cruisers list and don't know where to start...thought I had the problem solved.


Going to pull off the vacuum line to the MAP sensor tonight and see if it's ok.
Other than that I'm confused at having the same issues as before.
I don't know where to start.


Thanks!~John

cruiser54

What Tips have you done so far from my list?

jretzky

I started cleaning up some of the connections, but other than that I haven't done any.

Quick question... I just pulled off the MAP vacuum line from the throttle body and it appears to have o 2 holes.
o
The top one doesn't have any thing going to it and is open.
The bottom one is going to the MAP sensor.
Could something be missing? Like a vacuum plug.

Can't understand how the jeep ran great for a week straight.

Thanks!~John

cruiser54

Normal. See the photo.

Do the tips regardless. Let's not get overly academic about this.

DFlintstone

If you meant "revving" with no petal, my 90 has done that from time to time. It was the connector/plug on the IAC. The socket faces up so it can get water in there more easily. I had even removed, cleaned/checked the IAC a couple of times. Later, a better cleaning of the plug seems to have cleared it up.
Before I found that, sometimes I'd just shut her down and restart, and it would idle right. You might try that, then also messing with that plug to see if that changes anything. If it does you might have it narrowed down some.

Don't worry about the top hole, doesn't go anywhere. The MAP tube on the other hand needs to be perfect....no cracks or restriction.

Listen to Cruiser! Check/clean the grounds...

jretzky

So I checked the vacuum line from the MAP sensor to the throttle body and it is in perfect shape and I blew through it and it was clear.
I started up the engine last night and took it for a ride and it was fine.
Ran great!-no problems. I pulled off the vacuum line and it ran terrible, so I know it is good.


Yesterday morning when it was acting up the motor was running with no response to the gas peddle except stepping on it made it backfire. I put it in reverse and it back fired and then the engine responded to the gas peddle again and I drove it in reverse back to the top of the hill.


The problem has something to do with it sitting for the two days over the weekend. It has acted up for two weeks now only on Monday when it sat.


Ok!~I am cleaning and checking grounds and the connection to the IAC tonight after work. All the connections are oily and dirty, especially the coil.


I got my work cut out!~John

cruiser54

Make sure your engine to trans bolts are all there and tight

cruiser54

like this

jretzky

I look at it tonight. I replaced the crankshaft positioning sensor when I replaced my clutch last year, but my trans guy had to pull the trans again due to problems.
They are some kind of star head bolts. One of my friends replaced them with regular bolts on his Jeep.
John

jretzky

It turned out that the CPS wires were touching the exhaust.
Cruiser you were right.
Only about 3 inches are burnt.
The ends and most of the wire appears to be good.
Do you think I can just splice in some new wires?
My trans had to be pulled a second time and it appears the star bolts were changed out for standard ones and torked in there pretty tight.

I had a six point socket, swivel, 2 extensions, and a ratchet and they popped when I broke them loose.
Hope this is the engine problem.
Going to splice them tomorrow and put it back in.
Thanks!~ John

DFlintstone

Put the shrink tube on first, solder, then slide the shrink tube down and shrink.


CPS;
11mm socket > 3 inch extension > universal > long (18-24 inches of extension). Your feet are sticking out under the passenger side, you can reach up past the front drive-line with your left hand to hold the CPS from the front. Your right hand is on the ratchet way back by the tranny cross member. If you tie a long string on the old plug, you can use it to haul up the new. Toss that piece of plastic if it's still there, and do not drop the bolts in there! Echlin # CSS980, (from Napa, for 87-90), should be fine, but some prefer to go to Jeep. I wouldn't bother with anything else for that.

If your left forearm is bigger than a quart Mason jar, you might consider removing the front drive-line. Also You might cut your old CPS wires if they go through a deal on a bell housing bolt, then be sure your new are held somewhere safe.

cruiser54

Yes.^^

jretzky

I cut the CPS wires and soldered in a couple new wires.


I have to take out about 6 inches...really burnt.


Still don't understand why it ran good sometimes?


What does the CPS do?


I'm sure it's not going to be fun to try and get the bolts started (and keep the sensor in place) today after work.


I took off the ground cable connected to the dip stick tube and the insulation is really cracked and about 8 inches from the tube the cable is bare and oily. Going to get the new one at Napa like suggested.


Going to keep working on cleaning things up and installing better grounds.


Thanks!~John

jretzky

Replaced the CPS back on the trans and made sure they cleared the exhaust with zip ties.
The Jeep ran great last night and you know it...
it fell on it's face again this morning.
The engine was running and this time when I stepped on the gas it surged (stop & go).
There wasn't any back firing into the exhaust, but the engine died a couple times.


Changed the battery ground and clean up the other 2 grounds to the oil dip stick tube.


Other than that I can't figure out why it won't run right some mornings.


Still thinking something wrong with the fuel pump I replaced last year.


Appears to be doing the same thing a year ago.


Heard it could be the fuel filter, what do you think?


The weather has been dry and hot in southeast Mt.


Thanks!~John


PS. In the evening it runs great.

cruiser54

You can test fuel pressure.