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Renix 88 XJ hesitating during acceleration

Stone4140

NAXJA Forum User
Location
Caledonia,NY
I live in Western NY and recently had a 88 Cherokee shipped up from Virginia. I love it, but I’m having an issue with it losing power during acceleration or hesitating. It feels like a misfire, but I’m not sure. As normal maintenance I did the rotator, caps, plugs and wires. I noticed that all six plugs look like they were running lean. I’ve also done the first few steps in Cruiser54s checklist and plan to complete more this weekend. I also replaced the fuel filter, to no avail. I know I have to do some diagnostics, but is there anything that the change in climates could effect? PO sAid he had no issues like I’m experiencing. Suprisingly my searches haven’t turned up much regarding lean spark plug conditions.
 
Plugs usually look pretty lean to me.
Altitude is compensated for by MAP.

Get Tips 1 through 5 thoroughly done before anything else.
Where are you in Western New York?

Make sure the intake manifold bolts are snug.
 
Plugs usually look pretty lean to me.
Altitude is compensated for by MAP.

Get Tips 1 through 5 thoroughly done before anything else.
Where are you in Western New York?

Make sure the intake manifold bolts are snug.


Cruiser54 I kinda feel like I'm talking to a famous person:) I printed and have been reading your Renix Tips for the past few weeks. I'll post again when I finish the rest of the tips 1-5. I basically got the Renix Cherokee because the support I found online was solid. I have an MG as well and I found that forum support was essential for owning a classic vehicle.

On a different topic do you recommend the NickinTimeDesign REMII Engine Monitor? It seems like a valuable tool. My mechanic did my inspection yesterday and is asking his Snap-On guy today for an adapter to help diagnose, but I'd like to be able to do most of the work myself.

Thanks for the fast reply
 
FIRST do EVERYTHING that Cruiser54 recommends!

Here's is something simple "fix" I do on many different types of engines that are down a little on power. It has worked very well for me for many years. I've noticed over the years, in many engine rebuilds, that the oil drain-holes in many piston deigns are inadequate and create problems. Since the "oil- squirter" holes, in the connecting rods, are always throwing oil on the cylinder walls, a problem develops when the piston oil drain-back flow, to the crankcase, is reduced. The oil then "pools" around the rings and then solidifies/carbons-up and locks the piston rings in a "closed position" on the piston. Since the piston rings are locked closed (i.e. no tension against the cylinder walls) the compression gases blows by the rings and slight power losses occur. The "fix" is simple and inexpensive to do. If the piston oil drain-back hole is a very poor design, you just continue to do the "fix" on a regular maintenance basis.

Here's what I do:
1. Buy some Gumout; which has solvents for oil and gasoline lacquers.
2. Pull all the spark plugs and spray the WHOLE can of Gumout equally into ALL the spark plug holes. Let it set overnight.
3. The Gumout will dissolve all the lacquers and dried oil, from the piston rings, and then drain-back into the crankcase where the solvents will evaporate. The rings will then snap-out and contact the cylinder walls, as they were designed to do, to reduce compression gas blow-by and restore power.
4. The next day, replace ALL the spark plugs and fire it up. You'll get a little white smoke at first then it will clear up.

Best regards,

CJR
 
FIRST do EVERYTHING that Cruiser54 recommends!

Here's is something simple "fix" I do on many different types of engines that are down a little on power. It has worked very well for me for many years. I've noticed over the years, in many engine rebuilds, that the oil drain-holes in many piston deigns are inadequate and create problems. Since the "oil- squirter" holes, in the connecting rods, are always throwing oil on the cylinder walls, a problem develops when the piston oil drain-back flow, to the crankcase, is reduced. The oil then "pools" around the rings and then solidifies/carbons-up and locks the piston rings in a "closed position" on the piston. Since the piston rings are locked closed (i.e. no tension against the cylinder walls) the compression gases blows by the rings and slight power losses occur. The "fix" is simple and inexpensive to do. If the piston oil drain-back hole is a very poor design, you just continue to do the "fix" on a regular maintenance basis.

Here's what I do:
1. Buy some Gumout; which has solvents for oil and gasoline lacquers.
2. Pull all the spark plugs and spray the WHOLE can of Gumout equally into ALL the spark plug holes. Let it set overnight.
3. The Gumout will dissolve all the lacquers and dried oil, from the piston rings, and then drain-back into the crankcase where the solvents will evaporate. The rings will then snap-out and contact the cylinder walls, as they were designed to do, to reduce compression gas blow-by and restore power.
4. The next day, replace ALL the spark plugs and fire it up. You'll get a little white smoke at first then it will clear up.

Best regards,

CJR


Sounds like solid advice. I will do that fore sure. Would using seafoam or other similar products in the oil assist as well? I've read to pour a bottle in, run it for 10 minutes and then change the oil out. I plan on doing an oil change this weekend anyways. I'll be grabbing some gumout as well. Thanks,
 
I like the Gumout better, because it puts the solvent directly where the problem is. When you pull pistons from an engine, which has the rings locked closed, and spray them with Gumout it takes a couple of seconds/minutes before the rings snap open to their normal position..

Best regards,

CJR
 
I completed steps 1-5, replaced the O2 sensor and sprayed the cylinders down with Gumout. Each step seemed to help and after replacing the O2sensor there is no more hesitation. The Gumout trick actually bumped the compression of the number 4 cylinder up to where the rest were. Thanks for all the tips and advice. I have Nicks monitor coming tomorrow so if the issue comes back up I’ll be able to better diagnose what’s going on. Thanks
 
I completed steps 1-5, replaced the O2 sensor and sprayed the cylinders down with Gumout. Each step seemed to help and after replacing the O2sensor there is no more hesitation. The Gumout trick actually bumped the compression of the number 4 cylinder up to where the rest were. Thanks for all the tips and advice. I have Nicks monitor coming tomorrow so if the issue comes back up I’ll be able to better diagnose what’s going on. Thanks

Nicely done!!
 
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