chastings

Just thought I’d update. Huge thanks to Ohm! The return line was clear but the vacuum can for the FPR had ruptured and literally flooded the intake manifold with fuel. The regulator was replaced, the intake was siphoned dry and the oil has been changed (the crank case probably had 3 quarts of fuel mixed with the oil. I’ll change the oil again after a few hundred miles but the truck is back on the road. Thanks, everyone!

I did test it today and it showed 40psi at the Schraeder valve when cranking, but no idea how much was going through the vacuum line. I removed The fitting to the intake, cycled the key and fuel literally sprayed out of the vacuum line.

I suppose I need to replace the regulator before going any further as well

So, there’s still some gas in the intake manifold but won’t start. What else should I check? Are there any sensors that could’ve been damaged from raw fuel filling the intake?

Haha, son of a b*@ch! It’s pouring fuel from the regulator into the intake through the vacuum line.

Ok, thanks. Voltage during cranking at D1 is between 10.7-11.0 volts also, this is bizarre, but I opened the butterfly to squirt starting fluid into the intake and the intake is half full of fuel (I assume). The truck won’t sneeze or fire at all.

Nope, this is an earlier 87 and does not have the resistor

I did these yesterday, yes the rockers are moving and there is compression. At this point, guessing it sounds different (big guess) because there’s no fuel being squished in the cylinders. If working on the block ground and fuel pressure checks but still won’t start, I’ll tow it to the local Jeep mechanic. Everything seems correct but it could be something with the fuel pump or timing. strange, it literally went from running perfect to running on basically half the motor and then not wanting to start at all.

I have not, I don’t have a tool to test it. But it seems to put out adequate fuel. I can open the schraeder valve and fuel sprays out. Additionally, there’s a strong fuel smell each time I cycle the key. After replacing the fuel filter, the first time I cycled the key there was fuel coming out from the filter outlet. I had to retighten it even more. At this point, it appears to be getting plenty of fuel but I could be wrong. Any recommendations for a gauge to check fuel pressure on a 4.0?

Ok, so, I‘ve replaced the spark plugs and verified that they are firing by grounding one against the rocker cover. The truck does seem to sound different than it used to (can’t describe it) when it cranks. It seems fast but gives no indication it wants to start. Also, I smell gas but the plugs seem dry when I removed them for inspection. I guess I’m going to work on the ground at the dipstick to see if I can get it closer to 0 ohms (currently almost at 4.0). also, should the crank sensor generate 8.0 AC volts?

Ok, so, I’ve done cruiser tips 1-5 (excluding 4). 4 was not done because the truck is not at the house and I didn’t have any torx tools with me. Additionally, I put the timing light on the truck and I do appear to have spark (so 4 may be a moot point anyways). I double checked the crank sensor and it’s basically .8 ac volts i double checked the sensor grounds and they’re steady at 3.9 ohms

Thanks! I’ve actually performed 1, 2 and part of 3 so far but ran out of time. I noticed I could smell gas and there is fuel pressure at the rail as well. I’ll finish up tips 3, 4, and 5 and follow up

I'm having issues with my 87 4.0 Comanche and not sure where to start. It has spark and seems to crank relatively fast. I started with the crank sensor but not sure if I tested it right. I probed the + from my voltmeter to the red wire and the - of the meter to the white (coming off the cps). When cranking it basically shows .8 volts (which seemed high). It was running fine when I pulled out of the driveway but it needed power steering fluid. I turned it off, topped up the fluid, fired it back up and it immediately felt like it was running on only half the motor. I pulled it back into the driveway and it wouldn’t restart. Curious where else I should look. Thanks

Thanks cruiser. I've done 1, 3, 4 and 7 over the last 3 years. I did the ground refreshing when this first came to light late last year. I'll probably swing by my local Chrysler dealer and get a cps from them.

Mine has a center belt added to the existing bolts. As others have already said, very easy and a non issue. I had mine recovered last year by a local shop. It's nothing fancy, I think it was maybe 125.00

Current post is regarding my 89 Cherokee but I've been quite pleased with the responses on this board regarding my Comanche so figured I'd post it here. Sometimes when I crank the jeep it cranks a little bit slower than usual (just slightly), the tachometer starts jumping around, there will be a slight cough, the cranking speed slows then it stops cranking completely. I turn the switch off and try again and it usually starts the next try. It doesn't always do this, maybe once every 20 starts or so. The battery is a new napa legend with new cables. I tested the crank sensor a few months ago. It showed .4 ac volts indicating it is weak--also, when I unplug the crank sensor it cranks much faster. Since it tested marginal I think I'll replace the crank sensor and see what happens. But this is such a bizarre sequence of events it seems that I may have another issue that's contributing to my starting issues. When this occurs it seems as if it's trying to fire at the wrong time during the start sequence, throwing off the crank speed. Fwiw it runs fine, no issues other than an occasional hard start Thoughts.....

I'm not ok with this either. I've printed up all cruisers tech write-ups and stuffed them in my shop manual. He's always been the first to respond and has been spot on from my u-joint problems to my tps. He's probably the reason I own a mulit-meter....... Hope you come back

Thanks, good to hear!

I haven't tested one in a while, but I think I used to disconnect the cps from the harness, probe pos find good ground for neg, select to ac volts and look for roughly 1 volt while cranking? Might be wrong, but close.....

I had a trip Wednesday morning, drove the faithful manche to the airport and by the time I got there my truck developed a pretty nasty vibration. I noticed it after passing a semi. I could hear a slight roar and feel a vibration through the shifter, the clutch pedal, the brake pedal and somewhat in my seat. The noise sounds like it was originating in the back, but I've been wrong before. At slow speeds everything is normal; transmission sounds the same, no strange noises, but once above 60 there is a very noticeable vibration. It doesn't matter if you're neutral (coasting on the freeway), in gear, or in gear with the clutch engaged, the vibration won't go away until the speed is signigicantly decreased. It doesn't feel like a tire/balance issue, it doesn't quite fit the bill for bad carrier bearings either. I'm leaning towards u-joint or maybe even a loose wheel? I was late for my flight so I couldn't even investigate... but I return tonight and may have to either limp it home (after checking lug-nuts) or have the wife pick me up after I remove the d-shaft. The slight roar has me scratching my head, if I weren't 1500 miles away I'd have it diagnosed and fixed by now.... Thoughts?

I bought an aluminum 2 core rad from radiator classic? on eBay. Cost around 130.... I've ran it for a year with zero complaints

After driving it a couple days its now apparent that what I'm hearing is just the fan surging. Engine Rpm remains the same but if I hold the shift until 2800 occasionally you hear the fan clutch increase in speed or surge. Relieved its nothing significant. I replaced the fan clutch last February, looks like its time to replace it again

Found this site a few years ago, they're all pretty funny but this one seems fitting since its about a Comanche http://www.dontevenreply.com/view.php?post=107

Sorry, I should've mentioned that I don't doubt you; as I wouldn't put it past our government... I just wanted the opportunity to educate myself as well. I'm on several gun forums and haven't heard of it yet. Thanks for posting a link. Just last night I mentioned that while the majority of our guns aren't "technically" registered, ffl holders maintain a gun book and can always be utilized to start the paper trail.

Source?