chopper35nj Posted May 18, 2018 Share Posted May 18, 2018 Hey guys, haven’t been here in a while, but l am stumped. I just did a fresh engine build for my 89, my block was bad so l got a 1992 block that came with a 1994 ho head. Here are the specs. 030 over, new pistons, new rings, new bearings, new cam, lifters, push rods. Head was plained, fresh valve job, (leak tested) valve guids well within spec, new valve seals. Engine starts and ldles perfectly, won’t rev at all. I have indexed the distributer (new), set the TPS, coil is new as of last spring, new plugs, new injectors (volvo), IAC valve cleaned and functional, EGR functional, fuel pressure 31psi. Vacuum tested 17 inches of mercury at idle. 4 additional and large grounds. HELP!!! Please. FB455A41-F34C-4DD1-AE73-22C5D7A94698.MOV Link to comment Share on other sites More sharing options...
dkenitz Posted May 18, 2018 Share Posted May 18, 2018 No idea if this applies to your situation, but my perfect idle and misfire on rev problem was solved by a new Mopar CPS. Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 18, 2018 Share Posted May 18, 2018 which flexplate did you use Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 Stock 89 flex plate. Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 I just checked CPS and got 0.00v plug it back in starts right up, what gives? Link to comment Share on other sites More sharing options...
saveevryjp1998 Posted May 18, 2018 Share Posted May 18, 2018 Those suckers act up sometimes. I had one that would randomly get clogged up from oil leaking from the back of valve cover till I figured out it was missing a bolt in back.(the last one you can't see) I thought it was a bad main seal. It was my first xj and after years of owning inline 6s now its never been a main seal but bad valve covers gaskets with loose bolts every single 1. The cps's will also pick up chunks of metal and become magnetized with bad signal that way. My 2nd xj with the pukegoat, had a cps that was pulled to clean metal shavings off at least 3 times and started back up every time. Link to comment Share on other sites More sharing options...
dkenitz Posted May 18, 2018 Share Posted May 18, 2018 The old CPS which allowed my truck to idle perfectly yet not rev was worn down and had plenty of clutch material etc. on the magnet. Testing with a meter gave me false hope as well. Cleaning it helped briefly but it was too far worn. I found a new Mopar CPS on eBay for ~$32 so if yours is old or questionable I would suggest replacing. The local advance auto version did not work and seemed to not fit correctly, FYI. Link to comment Share on other sites More sharing options...
Ωhm Posted May 18, 2018 Share Posted May 18, 2018 1 hour ago, chopper35nj said: I just checked CPS and got 0.00v plug it back in starts right up, what gives? AC scale for voltage check. Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 OK, so how am l getting no voltage and running??? I went and checked it 4-5 times just to eliminate my own personal stupidity and ineptitude from the equasion. Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 2 minutes ago, Ωhm said: AC scale for voltage check. Yep, 200vac. Also checked all other ac volt ranges just to be sure. And, no, it isn’t a cheepo metre. Link to comment Share on other sites More sharing options...
Ωhm Posted May 18, 2018 Share Posted May 18, 2018 200vac range is high for this reading. Set a 20vac range. Should see up to 2.5vac reading. EDIT: I see you changed ranges. Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 Yep, checked every voltage range. Got nothing but zeros. Link to comment Share on other sites More sharing options...
chopper35nj Posted May 18, 2018 Author Share Posted May 18, 2018 Anybody have the part number for the MOPAR CPS for an 89 4.0? Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 18, 2018 Share Posted May 18, 2018 33 minutes ago, chopper35nj said: Anybody have the part number for the MOPAR CPS for an 89 4.0? T0739789 Link to comment Share on other sites More sharing options...
chopper35nj Posted May 19, 2018 Author Share Posted May 19, 2018 Thanks HOrnbroad, any opinion on the crowne automotive part? Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 19, 2018 Share Posted May 19, 2018 https://www.factorychryslerparts.com/products/Jeep/SENSOR--Engine-Speed-1987--SENSOR--Engine-Speed-EFI-Engine/4605308/T0739789.html https://www.moparpartsgiant.com/parts/mopar-sensor-g~t0739789.html Link to comment Share on other sites More sharing options...
Jeep Driver Posted May 19, 2018 Share Posted May 19, 2018 https://www.ebay.com/itm/Jeep-CHRYSLER-OEM-1987-Cherokee-Vehicle-Speed-Sensor-VSS-T0739789/222681283505?epid=83250821&hash=item33d8d6bbb1:g:i-gAAOSwVA5Z5c1u Link to comment Share on other sites More sharing options...
HOrnbrod Posted May 19, 2018 Share Posted May 19, 2018 2 hours ago, chopper35nj said: Thanks HOrnbroad, any opinion on the crowne automotive part? Junk. C.R.A.P. part. Link to comment Share on other sites More sharing options...
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