I am doing a full restore on my 87 YJ. I am keeping the 4.2L 258 engine and doing an ax15 swap. Planning to run 35's with 4.56's. I have been reading about conversions for EFI. Many of the forums I saw are older and wonder if there are any new technologies/upgrades. I would also like to run an in-tank sending unit with the EFI. Is there a kit out there? Sorry if this has been asked before, but everything I seem to find is for the 4.0 or the 4.2 in the CJ's.
1987 YJ 4.2L EFI conversion with in tank pump suggestions?
- Thread starter chubbs071
- Start date
If I was going to EFI today, I personally would be looking at the Holley Sniper. It is throttle body injection and not multi port but I believe it is the best option. I think it’s pricey, but I also think new carbs are pricey.
Howell kit D452 for 87 to 91 4.2 wrangler's. On my smog monster 86? CJ you removed ALL the crap, nuttered it and away you went. Personally I like the frame mount pump better because when the cheap china crap dies you wont have to drop the tank in the middle of BFE.
topic 1, the horror of oem BBD carbs. and worse its electronic carb controller(MCU), sure no lack of posts on this topic, here
Search BBD (find it)
one can also use the old(sold new still) external pump from the classic, "google Crown Vic fuel pump" External tank pump."
but of the old tank is full of rust and green slime gunk, no TBI injector made allows for that . so new tank too, and EFI type.
The pumps you use (wrong) for your FPR Unknown now can be too powerful and overload the FPR, and so easy to on the say 99 jeep FPR MPI. (if the pumps GPM is too high and shunt pressure too high (our is 75psi) then it fails. this is step 1 engineering facts.
EFI comes in 3 forms, which way you go is your call, price, down time, or labor or tuning costs.
1: OEM off say 1995 or go 1996 up OBD2, OEM jeep, (yes 4.0 tunes may work for the 4.2)
2: custom pre tuned EFI for your 4.2L engine PnP ready. HOLLEY?
3: custom ECU from say megasquirt and with free tuning, maps from other persons that have 4.2L jeeps, you do know if the 4.2 is modified heavy the tune of others are now now good for you, or the revs. (case in point bored max + stroker kit)
but there is no OEM EFI for The 258 cu in (4.2 L) was produced from 1971 through 1990
it all ended 1990.
1990 Jeep Wrangler Sahara 4.2 Engine, ends (off the cliff) and 4.0L now.
that matters for finding free tuning maps for any new buy of ECU, custom.
the EFI hardware is cheap (low cost) and only tuning is labor intensive, and dyno time to get there and all that labor is not cheap.
one more consideration is what needs to work in the dash cluster , odometer too? speedo sure. or use GPS speedo.
The fuel maps for 4.0 may work,
the other problem is spark. modern EFI runs 100% of spark 1996 up, for sure.
the problem is , how many cars today 1987 with 4.2L AMC engine is still on the road and or doing coversions, (tiny if all all)
the next problem is spark ,
the stock BBC 4.2 runs ,a dizzy mech, pure advance so you keep that and run ECU with no spark controls?
so planning to run the stock DIZZY
here it is , FSM quote
if yes, a fuel only TBI system can be tuned, (and if not using a EGR valve , stopping ping can be hard, the simple sure is running richer fuel maps) the CR is 9.2:1 compression ratio. so not too hard to avoid ping.
the static time is 9 D-BTDC (below is engine degrees not dizzy on a test stand)
if the dizzy rusts in side, the fly weights inside jam and no advance and power is now weak
same goes for cracked vacuum advance diaphram. we look at that first.
the OP never said why do TBI
but 1000 new TBI will never fix the bad DIZZY , ever. (those $1600 kits are zero spark ECU)
try a new VAC advance first and clean the advance weights and the rusted do zero spring bad or missing.
Search BBD (find it)
do you mean fuel pump or dash fuel level? or both , sure. none now so....
one can also use the old(sold new still) external pump from the classic, "google Crown Vic fuel pump" External tank pump."
but of the old tank is full of rust and green slime gunk, no TBI injector made allows for that . so new tank too, and EFI type.
The pumps you use (wrong) for your FPR Unknown now can be too powerful and overload the FPR, and so easy to on the say 99 jeep FPR MPI. (if the pumps GPM is too high and shunt pressure too high (our is 75psi) then it fails. this is step 1 engineering facts.
EFI comes in 3 forms, which way you go is your call, price, down time, or labor or tuning costs.
1: OEM off say 1995 or go 1996 up OBD2, OEM jeep, (yes 4.0 tunes may work for the 4.2)
2: custom pre tuned EFI for your 4.2L engine PnP ready. HOLLEY?
3: custom ECU from say megasquirt and with free tuning, maps from other persons that have 4.2L jeeps, you do know if the 4.2 is modified heavy the tune of others are now now good for you, or the revs. (case in point bored max + stroker kit)
but there is no OEM EFI for The 258 cu in (4.2 L) was produced from 1971 through 1990
it all ended 1990.
1990 Jeep Wrangler Sahara 4.2 Engine, ends (off the cliff) and 4.0L now.
that matters for finding free tuning maps for any new buy of ECU, custom.
the EFI hardware is cheap (low cost) and only tuning is labor intensive, and dyno time to get there and all that labor is not cheap.
one more consideration is what needs to work in the dash cluster , odometer too? speedo sure. or use GPS speedo.
The fuel maps for 4.0 may work,
the other problem is spark. modern EFI runs 100% of spark 1996 up, for sure.
the problem is , how many cars today 1987 with 4.2L AMC engine is still on the road and or doing coversions, (tiny if all all)
the next problem is spark ,
the stock BBC 4.2 runs ,a dizzy mech, pure advance so you keep that and run ECU with no spark controls?
so planning to run the stock DIZZY
here it is , FSM quote
if yes, a fuel only TBI system can be tuned, (and if not using a EGR valve , stopping ping can be hard, the simple sure is running richer fuel maps) the CR is 9.2:1 compression ratio. so not too hard to avoid ping.
the static time is 9 D-BTDC (below is engine degrees not dizzy on a test stand)
if the dizzy rusts in side, the fly weights inside jam and no advance and power is now weak
same goes for cracked vacuum advance diaphram. we look at that first.
the OP never said why do TBI
but 1000 new TBI will never fix the bad DIZZY , ever. (those $1600 kits are zero spark ECU)
try a new VAC advance first and clean the advance weights and the rusted do zero spring bad or missing.
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Is the Howell kit still available, I looked for that awhile back and didn’t find it?
Ok just did a search and it came right up. Maybe I was spelling Howell wrong before. Forgive a dumb hillbilly.