4.0 L timing

[zaconrad]

Hello everybody, 

I have a jeep 4.0l with an aftermarket ecu. I was wondering what the cranking timing, and idle timing are.

[ghetdjc320]

15 hours ago, zaconrad said:

Hello everybody, 

I have a jeep 4.0l with an aftermarket ecu. I was wondering what the cranking timing, and idle timing are.

Oooh tell us more! The 4.0 was always computer controlled and the timing was not adjusted. The distributor was simply “phased” into the correct position and the ecu ran the timing off of its preprogrammed table. That being said I know WOT timing is a conservative 28* on both obd1 and obd2 4.0’s. Base timing is probably somewhere between 10-14. I’m adjusting my timing on my built 4.0 to 14* at idle with 34* all in. If you wanted to be a bit more cautious 12* base and 32* all in would be a good place to start. 
 

how are you adjusting timing? Are you reprogramming the ecu or do you have an hei installed? 
 

Please let us know what sort of stand alone ecu you have on your rig. Pics would be great. 

[cruiser54]

Hate to be Captain Obvious here, but we need to know the year of your 4.0,,,,,,

[Cummins93]

This is completely stolen and I take zero credit for it...and zero responsibility for what people do with it.

[ghetdjc320]

7 hours ago, cruiser54 said:

Hate to be Captain Obvious here, but we need to know the year of your 4.0,,,,,,

Why would that be helpful? The op has an aftermarket ecu. Knowing the cam specs may be nice if not stock though. 

[ghetdjc320]

46 minutes ago, Cummins93 said:

This is completely stolen and I take zero credit for it...and zero responsibility for what people do with it.

Can’t quite read the numbers off of the table. Looks like an HP tuners map 

[zaconrad]

On 8/28/2021 at 11:42 PM, ghetdjc320 said:

Oooh tell us more! The 4.0 was always computer controlled and the timing was not adjusted. The distributor was simply “phased” into the correct position and the ecu ran the timing off of its preprogrammed table. That being said I know WOT timing is a conservative 28* on both obd1 and obd2 4.0’s. Base timing is probably somewhere between 10-14. I’m adjusting my timing on my built 4.0 to 14* at idle with 34* all in. If you wanted to be a bit more cautious 12* base and 32* all in would be a good place to start. 
 

how are you adjusting timing? Are you reprogramming the ecu or do you have an hei installed? 
 

Please let us know what sort of stand alone ecu you have on your rig. Pics would be great. 

Sorry for the super late response:(

It's a 1995 engine. I boarded and stroked it to a 4.6 with 10.5:1 compression. I did put a aftermarket cam in it. It's a comp cams Extreme 4x4 218/226. Specks are, 218 @ .50 for the intake, 226 @ .50 for the exhaust with a lsa of 111.

The EFI system is were it gets interesting. As far as iv seen I am one of the first if not the first person to use a Holley Terminator X MPFI system with the 4.0 paried with the Holley hyper spark distributer and coil for the AMC 4.2. 

Currently I have it set up with 9 degrees at idle 37 degrees at cruse, and 34 degrees WOT.

[ghetdjc320]

3 hours ago, zaconrad said:

 

Sorry for the super late response:(

It's a 1995 engine. I boarded and stroked it to a 4.6 with 10.5:1 compression. I did put a aftermarket cam in it. It's a comp cams Extreme 4x4 218/226. Specks are, 218 @ .50 for the intake, 226 @ .50 for the exhaust with a lsa of 111.

The EFI system is were it gets interesting. As far as iv seen I am one of the first if not the first person to use a Holley Terminator X MPFI system with the 4.0 paried with the Holley hyper spark distributer and coil for the AMC 4.2. 

Currently I have it set up with 9 degrees at idle 37 degrees at cruse, and 34 degrees WOT.

Terminator x has been used to power the 4.0 using stock cam and crank triggers. It was a mess to setup but it has been done. The hyperspark is the way to go, only downside is you loose cam timing for for full sequential. Still an very nice setup though. The 4.0 will like a bit more timing at idle (around 12* makes them happy). Which injectors are you using? 

[zaconrad]

 

So I am using the Holley Hyper Spark System so I can control the time through software. For me sequential was not that important.

I'm running the Ford Blue large body 24 lb injectors. The one thing that I had a problem with is that since their Ford injectors their made to use a 42 psi fuel pump. On my Comanche I'm using a 60 psi Holley pump. What I did to solve this is I told the Holley software that the they were rated for 60psi and I also told the system that the engine was smaller than it actually is. 

[ghetdjc320]

2 hours ago, zaconrad said:

 

So I am using the Holley Hyper Spark System so I can control the time through software. For me sequential was not that important.

I'm running the Ford Blue large body 24 lb injectors. The one thing that I had a problem with is that since their Ford injectors their made to use a 42 psi fuel pump. On my Comanche I'm using a 60 psi Holley pump. What I did to solve this is I told the Holley software that the they were rated for 60psi and I also told the system that the engine was smaller than it actually is. 

What is your pressure regulator set to? If your using a stock style regulator on the fuel rail it will be set to 39psi. The fords are likely set to 3 bar (43.5psi) but some fords set the rates pressure at 39psi also. Keep the engine size correct. Set the fuel injectors up with the correct specs. Rated flow 24lbs at 43.5 psi. Actual system pressure (whatever the actual system pressure is). If you have no regulator and run the Holley pump at 60psi actual fuel pressure, the i hector pulse width will be far too low at idle. The terminator also requires the injector off time between 8-20v. Did you get that info in there? Let me know if you have any questions.

[zaconrad]

So super late update. I ended up putting the Edelbrock aluminum head on it with the smaller and better chamber design. I got it dyno tuned and it ended up making around 250whp. It seemed to like 29 degrees at wide open and 32 at cruse. I also live at in Denver CO so I'm around a mile above sea level.

[ghetdjc320]

Nice results