James Duff OHV engine chip

[malohnes]

Yeah,
I kinda thought about digging into that thread too! I actually read the whole thing once, but it was late in the night and I didn't absorb all the info past a certain hour in the wee morning!!!

I'll give it a try, its easy to get to the screen and verify.

I might try a 'stang MAF at some point later when I start a full engine rebuild where I can use larger injectors to match the MAF better.

 

[malohnes]

Okay, got my chip in the mail today. Installed and drove abound town. It definitely is noticeable in drivability and responsiveness, i.e. better. I need to do a longer drive next weekend, 4 hours round trip, 249 miles. I'll have a better handle on the real discernible differences.

 

[jd4242]

I personally believe any chip is worthless without major mods and especially on a obd1 truck..there is so little of parameters and lack of sensors that the gains will be noticeable only in your head..also alot of those chips is deceiving,the dyno graph is for a sohc 4.0,totally a different motor and obd2 ..i would bet all thats changed on those chips is the timing and maybe lean the injectors out some..both can be done in your garage in probably 5 mins..also if you already have a high milage motor or have pinging of any type, a chip will make it worse.hence the need for premium gas....

Also unless you have head mods,cam,p+p,bbk tb,headers and exhaust mods,a larger maf is not needed..the stock maf will support hp mods far above what any ohv will make NA..only after ALLL those mods are done is a tune really needed and a dyno tune is only way you get it dialed in perfect. .there isnt any cheap,common easy way of data logging and every motor is different. .SCT is only company that makes a chip thats programmable at about every dnyo shop..its the SCT 4 bank eliminator chip for the old fox bodys..

 

[Rhett]

Okay, got my chip in the mail today. Installed and drove abound town. It definitely is noticeable in drivability and responsiveness, i.e. better. I need to do a longer drive next weekend, 4 hours round trip, 249 miles. I'll have a better handle on the real discernible differences.

Is it a piggyback chip like my Apten? I'm assuming it is. You installed it on the ECU behind the passenger side kickpanel?

Are you supposed to use 93 octane with your JD chip?

 

[jd4242]

Is it a piggyback chip like my Apten? I'm assuming it is. You installed it on the ECU behind the passenger side kickpanel?

Are you supposed to use 93 octane with your JD chip?

Its a jet chip..as far as i know all obd1 are piggyback..

 

[malohnes]

JD - I respect your advice and opinion, as you've got a ton of great experience and knowledge to share that's been helpful to me and others.

My seat of the pants experience thus far is positive. Better than I expected and not as good as I hoped. Not having a dyno means no hard numbers as real evidence to show.

My engine is far from stock, but not a hard core engine either and it is over 145K in mileage as well. Aside from a rear main seal leak, my compression is great and I had original cross hatch patterns on my cylinder walls when I swapped heads 18 months ago. So my engine is pretty healthy and i'm not making any issues with the bolt on parts I have right now. My engine runs better with the chip. Idle is smoother and response is crisper, just like when I did the throttle cable mod and the TB shaft mod...not subtle, but not huge either.

I'm not concerned with how the chip just tweaks parameters, i'm more concerned with whether it actually does anything to the engine in a beneficial way. In my case it does. I'm certain it didn't give me 20+hp/35+tq as claimed, but I feel it has given me some increase. If I had a bone stock engine, I would not expect anything, but with the mods I have it seems reasonable that it enhances whats all ready there, like an exhaust or intake system mod.

Rhett - yes and yes. Though the octane requirements is 91+. I have water/meth injection so gives me the octane boost.

 

[jd4242]

JD - I respect your advice and opinion, as you've got a ton of great experience and knowledge to share that's been helpful to me and others.

My seat of the pants experience thus far is positive. Better than I expected and not as good as I hoped. Not having a dyno means no hard numbers as real evidence to show.

My engine is far from stock, but not a hard core engine either and it is over 145K in mileage as well. Aside from a rear main seal leak, my compression is great and I had original cross hatch patterns on my cylinder walls when I swapped heads 18 months ago. So my engine is pretty healthy and i'm not making any issues with the bolt on parts I have right now. My engine runs better with the chip. Idle is smoother and response is crisper, just like when I did the throttle cable mod and the TB shaft mod...not subtle, but not huge either.

I'm not concerned with how the chip just tweaks parameters, i'm more concerned with whether it actually does anything to the engine in a beneficial way. In my case it does. I'm certain it didn't give me 20+hp/35+tq as claimed, but I feel it has given me some increase. If I had a bone stock engine, I would not expect anything, but with the mods I have it seems reasonable that it enhances whats all ready there, like an exhaust or intake system mod.

Rhett - yes and yes. Though the octane requirements is 91+. I have water/meth injection so gives me the octane boost.

Yea with your engine the changes probably are more noticeable. Like you said did it give you the 20hp,i doubt it.im sure it did add some in your case that might be measurable but cost to hp gains would be bare minimum. So in most cases its not worth it till serious mods are done and when serious mods are done a dyno tune would be more practical. Im glad its working out for you though and thats whats important.

You can trick the ecm in other ways to adjust timing and a/f(crank sensor and tps) but can be bad if you dont know what your doing.biggest thing is for a 4x4 explorer any mods are gonna show very small benefits especially on a dyno

 

[malohnes]

There is negligable difference in fuel economy thus far. I'll have to do more long distance driving for that. And, with winter approaching in my area, its not the best time to gauge MPG in winter and inclimate weather!!! I'll post as I see changes one way or the other.

I don't see the mods you've made in my immediate future, but I am in contact with Morana Racing about some parts for my performance rebuild a few years down the road. I like to buy the parts and pieces as I go and can afford and then when I'm ready, go to town.

 

[Rhett]

I think most of the guys in this 1st gen subforum pretty much know the limitations of OBD1 and mostly vacuum trannys and tuning limitations for them.

1st gen forum always was full of gearheads, and now...even more so since all of our trucks are old. So yeah, I love the knowledge and experience of the people on here.

 

[Rhett]

There is negligable difference in fuel economy thus far. I'll have to do more long distance driving for that.

I don't notice any difference in mpg with my Apten chip, either.

JD mentioned TPS tweaking. I did do a TPS calibration about 10-12 years ago (when I got my BBK throttle body), and it has worked flawlessly since. TPS voltage can be tricky and since I am no expert, when I did mine I talked to Apten about it to make sure I didn't cause a problem.

That must be the TB shaft mod you mention?

 

[malohnes]

I don't notice any difference in mpg with my Apten chip, either.

JD mentioned TPS tweaking. I did do a TPS calibration about 10-12 years ago (when I got my BBK throttle body), and it has worked flawlessly since. TPS voltage can be tricky and since I am no expert, when I did mine I talked to Apten about it to make sure I didn't cause a problem.

That must be the TB shaft mod you mention?

Yeah! I need to check the TPS calibration again. I haven't done that since I did the shaft mod on my stock TB. I have since switched to a BBK TB. And I also did the shaft mod to it as well.

OBD1 has its limitations but an engine still needs to run well in balance with the components. We often think that a HP part for a racing engine should bump the performance of a street car/truck on the merit that it works on a racing application. That gear-head mindset sometimes causes us issues, particularly when it doesn't have the expected or desired affect.

Case in point is my engine. I know I'm making more power than stock but I think I would be surprised at how much I'm actually making. I think the effect of increase responsiveness and better drivability masks the lack of power increase.

With regards to fuel economy, in my case, I live in a really mountainous area and getting 21+mpg in this terrain would be getting about 24+ on flat terrain. I achieve this with my mods.

Its an interesting subject and it can be fun. I wish my truck wasn't my DD, but that's OKAY too. I can walk to work, the grocery store and all my errands stops...most people can't.

 

[malohnes]

UPDATE:

So, now that I have had some running time with the chip, around town and mostly on the hi way I have a better sense of the benefits of it on "my" engine. Your results may differ....

I re-calibrated the TPS sensor. Mine was off a fair amount, under by almost .2v at idle. Once reset and the engine ECU reset the truck really woke up. Now, responsiveness is very crisp, much better than before the chip and also before the calibration. It idles very smoothly and maintains 14.3-7 on my WB AFR gauge very well, except when I gas it and at lift off, in which case it enrichens and then goes way lean, respectively. Dramatically different to the stock behavior which was often flat and/or slow in response. This is mirrored when I drive, not just in neutral and no load revving.

We're getting light frost in the mornings now as fall is giving way to more winter like temps. Warm-up seems a bit faster with less hi idle time. I used to have to run with the shorting block removed to get ping free performance, without W/M and using 87 or 90 octane fuel. I now can run with it in place. Further, I am able to run a slightly more aggressive amount of Water/Meth and begin it earlier with the chip. I tune based off of the WB AFR gauge and by how the engine stumbles and stutters or runs smooth when injected with too much. currently, it pulls harder and can carry OD gear up major grades without slowing down so much. Often I used to need to drop to fourth to clear some grades without lugging the engine and now it goes up without troubles. It's pretty impressive in this regard and was the one thing I was hoping for but didn't expect. I still have the stock 3.55 gears....it doesn't help on these steep grades.

Fuel economy is lightly better, but I attribute that more to the W/M injection than to the chip itself. So far, after a 1000 or so miles of hi way driving, Im now getting 24mpg on the hi way. In town its the same and I expect winter time in town to be dismal as usual. I can't run the W/M until the truck is completely warmed up and when speeds are above 35-40 mph which precludes all my around town driving.

This chip may only be able to adjust timing and injector response and other small parameters of this simple EFI system, which doesn't seem to do much on paper, but it really made a difference in my application. I understand better now how limited an OBD1 system can be to OBD2 in this way.

So thats that. It works great for me, but maybe not for you if your have a mostly stock truck. My truck is breathing very well with stock internals and heavy bolt-on externals and I feel that is the main reason why I have the positive response with the chip, otherwise I think the money is better spent on other mods.

I hope this helps others out there who are considering a JD or JET chip for a first gen Exploder.