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Topic Review (Newest First)
07-27-2011 03:48 PM
Tyewilly All the distributor does on these engines, as far as spark is concerned, is send it to the right plug. If you have it out of time, the rotor won't be lined up with the correct, if any, terminal on the cap when the coil fires, sending the spark to the wrong plug. It sounds like you've got it lined back up right, but you may have burnt up the cap and rotor in the process.
07-27-2011 10:03 AM
Driller
Quote:
Originally Posted by dkdavenport View Post
Glad to here you ar back on track again, probably a little fine tuning and all will be good again. mine i took the tab that hods the dist. down and trimmed it up so i could actualy adjust the timing.
And iam about ready to leave this ugly country for good, i will retire in 15 days, been doing this for almost 40 years it is time to turn it over to the younger men.
God bless you man. Come home safe and sound. I salute you! Driller
07-27-2011 02:08 AM
dkdavenport Glad to here you ar back on track again, probably a little fine tuning and all will be good again. mine i took the tab that hods the dist. down and trimmed it up so i could actualy adjust the timing.
And iam about ready to leave this ugly country for good, i will retire in 15 days, been doing this for almost 40 years it is time to turn it over to the younger men.
07-26-2011 04:00 AM
pablo4953 A friend let me use his (known good) 95 2.5 5 speed to do some troubleshooting. At this point I am convinced I have a timing problem. So, I plugged in his computer, made no difference, still would not start. Then I tried his crank position sensor, still no joy. With the jeeps side by side, I compared everything I could see, but everything was the same.

I decided to check his timing............. With his #1 cylinder at TDC on the compression stroke, and the distributor rotor dead on the #1 position, his balancer timing mark was at 12:00, not even close to the zero mark (at about 10:00).

So I put mine at #1 TDC, my balancer was at 12:00 also, reset the distributor so the rotor was on #1, and I'll be damned the engine started right up! Took it for a test drive, and it is running reasonably well, although not as good as when I had it running before. Plus once it is warm it takes a little bit of cranking to get it started, but it does start.

I can understand the balancer outer portion (with the mark) slipping over time, but that is almost a 90 degree difference, and there are no signs of torsional yielding on the rubber? Oh well it is what it is, and the engine is running.

The engine used to start every time, cold or hot, on the first few revolutions when cranking the engine, plus it had a little more pep. So, although I know I am in the ball park, I want to fine tune the timing a little bit, but without any point of reference I am not sure which direction to go. I could experiment, and probably eventually end up where I need to be.

I have looked everywhere for a reference on degrees before or after TDC, but all reference says the timing is not adjustable. I did find reference on a Dodge forum for the 2.5, which stated 12 degrees BTDC, but I am not sure if that would apply. Any ideas?

DK I thought it was pretty cool that a guy in NC was helping me with this, but Afghanistan!! I am impressed that you would take the time considering the BS you must have to deal with! Good one on ya! I wish you could come and help, if for no other reason than you would not be there. Take care my friend!
07-21-2011 07:17 AM
Vabaco Don't know if this helps but my 87 wrangler did the same thing. I finally found a bad wire that would short out once everything got warmed up. It was sporatic and took a while to fix. Either it would run great, have no power, backfiring or wouldn't start.
More than likely you have an electrical problem.
07-21-2011 01:17 AM
dkdavenport I wish you were a little closer i would come give you a hand, but with you in the islands and me in Afgahastan it is a bit of a haul. but none the less i still feel that the mechanicals are all good, and it is down to electronics, and that is the hard part of the troubleshooting, but it still sounds like the ECM is not timing fuel and ing correctly, like i said the cam crank timing if it does line the marks up and the piston is tdc than at one point it should hit tdc and compression ing. all at the same time, I know most SBC i tend to get 180 out everytime i do one, got in the habit of doing all my cam crank timing off #6 that way it comes out right when i drop the dist. in. so maybe you could try going off #2 cyl i think that is the 180 mark from #1 fire order if i remember is 1,3,2,4 so 2 would be the 180 mark on the cam.
07-20-2011 03:28 AM
pablo4953 I sent an email to the company that built the engine, explaining my situation and asking about the timing marks being 180 out. They said they built three engines today, checked timing alignment on all three, and all were cam at 12 with crank at 12. So even though it is contrary to the manual, it is what it is.

They also said it sounded like I had a massive vacuum leak, and suggested I plug off the port to the brake booster and try it. I plugged the port, but it still would not start. What it did do was consistently (muffled) backfire through the exhaust. Sounds crazy, but I consider that progress, since I did not have that consistency before.

The engine company also wanted to know what my compression was. Cold with the throttle open I had; 1=198, 2=190, 3=180, 4=182.

I tried setting the distributor 180 out but I got nothing, not even a backfire.

I know I have spark, pulled all the plugs and connected each one to its respective wire, lined them up in firing order next to each other. Had the missus crank the engine. Had a consistent row of sparks in perfect sequence. Installed & connected everything back up, cranked the engine and checked each plug wire with an induction spark tester, had a nice bright spark for each one.

I know I have fuel, put a pressure gauge on the fuel rail, got system pressure (39 psi) during cranking. Pulled the fuel inlet line at the rail and put it in a jar and cranked for less than 10 seconds, got damn near a quart of fuel.

I know my injectors are firing, because I put a test light on each lead (in circuit), and each light flashes consistently while cranking. What I am not certain is if the injectors are opening. I assume they are, because if I pull a plug after a start attempt, although not wet, the plugs do have a strong fuel smell. I suppose I should pull the injectors, leave attached to the fuel rail, hold over a pan and physical watch them spray while cranking. I dread doing that, because the whole injector assembly was a real pain to install. But I might have to if I can't find anything else.

DK I agree with you, it seems to be a timing issue between fuel and spark, which is totally controlled by electronics. That's why I put so much effort into testing (as best as I could) all my sensors, and ringing out every wire from every sensor to the ECM. One thing I wish I knew how to test was the ECM. Even though it is new (rebuilt) I assume it is working properly, but don't really know, and at $270 a pop, it's a too expensive to experiment with.

DK I appreciate your input on this. It helps to bounce it off someone else. I'll keep scratching at it, and eventually figure it out. All suggestions are most appreciated.
07-20-2011 12:43 AM
dkdavenport If you dont see any differances in the fly wheel is correct, and it will only fit one way, sounds like it is a ing. or fuel issue, either not getting fuel at the correct time or no spark. as what you have said about cam to crank timeing there are no issues there, the mechanics of the dist sound good so i would look at eletronics, to make sure it is delivering fuel at the correct time, and if you are getting a good spark, drop the dist 180 out from where it was and see what it does, i have seen them run at about 90 deg out of time, but not running very well but start and run.
07-19-2011 03:15 AM
pablo4953 Also, I installed a new flywheel and clutch during the install. Although the replacement flywheel looked the same as the old one, it's not like I took any measurements or anything, so I guess the potential for it being different does exist.

I also thought that maybe I oriented the flywheel wrong (on the crankshaft) when I installed it, and it was affecting the crank position sensor, but the thing ran great for 50 miles or so. Plus I am not sure I could have oriented it wrong, as it took forever to get all the bolt holes to line up.

Still though, until I find the smoking gun, I have to consider all possibilities.
07-19-2011 03:00 AM
pablo4953 Thanks DK..........today I pulled the distributor, which is new, and checked the drive gear. It was secure and the pin was solid all the way through. I also pulled the cam sprocket to check the locator pin, which was also secure. There are two holes on the cam flange 180 apart, if the builder put the pin in the wrong hole it would account for my alignment mark being 180 out. But it looks like the other hole is too small for the roll pin, so I doubt that is the case.

The factory manual does call for the cam mark to be at 6:00 & the crank at 12. I do get two rotations of the crank for every one on the cam, but no matter how many times I try, the cam is always 180 out on #1 TDC on compression, and it matches perfectly at TDC on the exhaust stroke.

Just to eliminate the variable, I aligned the marks and reset my distributor to align with the #1 plug. Still would not start, not even backfire. At next opportunity I think I'll pull the push rods and look over the valve train with more detail.

Also, I forgot to mention in my last reply that the entire ignition system is new, as well as the ECM. I have also checked continuity and looked for ground shorts on every wire associated with the engine. All the engine sensors are new except the MAP, and all of them test good.

This one has really got me stumped. Thanks for your help.
07-19-2011 02:39 AM
anearthmonkey
Quote:
Originally Posted by dkdavenport View Post
The way the cam is ground it will only come up on compression one time during its two revoutions, the way i check is to watch #1 intake valve and when it closes the piston is on its way up when it reaches TDC than all of the marks should line up on the crank and cam, the ballancer will be off some due to the fact they have put some advance in to the ballancer and some times they tend to slip on the rubber band between the crank stub and the outer ring. usualy when i build motors i will use a degree wheel on the crank and a dead stop for tdc, then a dial indicator on the cam lobe to set cam to crank timing, but most stock motors i dont that fussy about a half degree on cam to crank. other than that i would check push rod length, if the block or head has been shaved once it warms up you may have to much push rod length and just holding the valves open just a touch. one other issue i have run into is there are two different flywheels, one for the port injection and one for the throttle body models.
the cam rotates once and the crankshaft twice during the 4 strokes
07-19-2011 01:16 AM
dkdavenport Found one source that says the cam is at 6 and the crank at 12. which is kinda what i remember, i have had some that were 6 and 6 but i cant remember which moter it was, i think it was a early ford. but it should not matter on the cam to crank timing either way it will still line up once every two revolutions, now just figure out which one is the compression stroke, that would be just after the intake valve closes, and piston reachs TDC that should be firing position for #1 cyl. set dist. in so rotor points dead on # 1 plug terminal. should be close enough to get it to fire, then fine tune.
another issue i have had is with weak coils/grounding, CPS over heating. the CPT try pouring cold water over it and see if it makes a difference. have limped several home that way.
07-19-2011 12:51 AM
dkdavenport The way the cam is ground it will only come up on compression one time during its two revoutions, the way i check is to watch #1 intake valve and when it closes the piston is on its way up when it reaches TDC than all of the marks should line up on the crank and cam, the ballancer will be off some due to the fact they have put some advance in to the ballancer and some times they tend to slip on the rubber band between the crank stub and the outer ring. usualy when i build motors i will use a degree wheel on the crank and a dead stop for tdc, then a dial indicator on the cam lobe to set cam to crank timing, but most stock motors i dont that fussy about a half degree on cam to crank. other than that i would check push rod length, if the block or head has been shaved once it warms up you may have to much push rod length and just holding the valves open just a touch. one other issue i have run into is there are two different flywheels, one for the port injection and one for the throttle body models.
07-18-2011 03:53 AM
pablo4953 Good point on the distributor. It is new, so I had not considered a problem with the pin that would allow the gear to slip. I'll pull it and double check.

One thing that I can't figure out, disregarding the distributor, is why the crank & cam marks won't line up at TDC on the compression stroke of #1 cylinder. If the marks lined up, I could reset the distributor, and should be good.

Before pulling the timing cover I would get #1 at TDC, line up the harmonic balancer to the zero on the timing cover, then position the distributor so the rotor was pointing at the #1 plug wire. At this point the only thing I can't see are the sprocket timing marks. Now that I can see them I can't get everything into alignment.

When I first installed the engine, before putting the timing cover on, I checked everything for alignment, and it was all good. It started great and ran real smooth. I had a problem with power under load, but changed out the crank position sensor, and it ran great until my current problem started happening.

It seems something has changed in the relationship between the crank and the cam, or I am screwing up the procedure at some point.

Thanks for your help.
07-18-2011 12:52 AM
dkdavenport The cam gear can only go on one way, same as the crank gear, so the cam and crank dots line up every two revolutions which is correct. the 180 deg. would be in the dist. to cam timing. Iam guessing the cam to crank timing is good, the next thing i would check is the dist. pull it and check the roll pin that holds the gear to the shaft, if it is sheared it will cause the timing to be all over the place, and check the cap for cracks, carbon tracing and moisture, all of which can cause miss fires.
07-18-2011 12:04 AM
pablo4953
timing problem??

I recently installed a rebuilt 2.5 in my 93 wrangler 5 speed. I had initial problems that were solved by replacing the cps, and it ran well for about 50 miles. It would be running fine, then kind of go flat and loose power, like I was flipping a switch, then it would pick up and run normal. It did this with more frequency, until finally it would not start.

I thought for sure it was an ignition based problem, and ran the gamet of all possibilties, with no success. It finally got to the point where it was consistently back firing thru the exhaust when cranking the engine. Since I know I had spark & fuel, and I had gone thru the timing procedure at least a dozen times, I decided to pull the timing cover and check my marks.

I am using a compression tester and turning the crank by hand to determine TDC on the #1 cylinder (plus a visual verification of the top of the piston). This is the only position where the #1 cylinder will make compression and hold it.

My problem is...........with the #1 cylinder at TDC, the crank sprocket dot is where it is supposed to be, but the cam sprocket dot is 180 out. When I line up both cam & crank dots, I am at TDC on the exhaust stroke.

Even though I have the Chrysler manual for this Jeep, I am still uncertain how the cam sprocket is keyed to the cam. Something is clearly wrong here, but I am having a hard time getting my head around how to correct it.

Any ideas would be most appreciated.

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