My PMO ITB Project

[Trog]

And to make matters worse, it's freezing out here. Went out tuning last night, and couldn't get the CHT past 93DegC.

Looks like I'll be heading to the dyno-man (right after the snow melts).

Cheers,

T

[jasonlee]

Trog, You must be off to the dyno now. Snow has stopped. At least in my hood. Great upgrade, looks and sounds fantastic. Nice work.

[elwood-914]

Very cool! Makes me want to think about a future build.
Thanks for all the info and pictures. Beautiful.

[frankc]

Trog,

Excellent write up - very good stuff.

I'm installing an Electromotive/Clewett system (XDi2 ignition only - sticking with the Webers for now) and was curious about the routing of the wiring harness from under the left seat. You mention that you followed the factory routing, but for those of us with pre-motronic cars, how did the factory route the harness? My original plan was to run the harness into the tunnel via the small hole that exists left of the handbrake, and then out the back of the tunnel up into the engine bay like the original engine harness, but this could be a pain to get to if I needed to for some reason. It seems the route you mention stays in the cabin and exits near the rear seats in the corner of the engine bay, is this correct?

I plan on using the same Clewett mounting plate for my DFUs - I like the idea of mounting the fuel pressure regulator there as well.

thanks,
Frank

[Trog]

Hi Frank,

You're correct, my routing hugs the door sill and exits near the bottom of the rear seats at the corner of the engine bay. I divided my harness into 2-parts. The drivers side containing the signals for the various engine sensors. The passenger side contained the signals for the ignition coil. The reason I decided to split the harness was to maintain maximum distance between the noisy coil signals, and the various other sensors (TPS, MAT, MAP, Crank, etc).

If you never plan to install fuel injection, then go ahead and keep the wiring on the drivers side as it's the shorter route.

Take note that the harness will exit the floor pan just ahead of the rear driver side wheel well. From there it travels up toward the top of the firewall (where the AC hose enters the engine bay).

Take care to protect the wire bundle from road rash as it travels beneath the vehicle.

T...

[dfink]

I brought mine along the drivers side as the stock did but then went up and exited to the engine compartment just above the rear seat where the fire wall turns flat again. You must be carefull not hit any fuel lines if you use this route. I will also have to seal off the hole. I didn't want to patch the cables as Trog did. I also mounted my control unit on the firewall and the coild are mounted on the engine compartment side of the firewall. I lowered my seat and there would not be room under it anyhow. I have twin plug so I have a few more wires stuff in also. If you do wide band. And I really suggest you do wide band then you have those wires also. If I were doing it over I am not sure I would do the full sequential injection. If you want/need connectors go to your local Harley dealer and get deutsche connectors. If you have removed the A/C the hugh green wire for the compressor clutch works great as a power supply for the coils

[frankc]

Trog,
It sounds like using the routing similar to the Motronic box would require a hole drilled through the tub at the floor near the left rear seat. I'd prefer to avoid that. I was thinking more along the lines of what Dfink said. Actually, there is already a small hole in my firewall in the left corner of the engine bay from when the PO had an after-market security system installed (ripped out by me immediately), so I could just use that.

So now I just need to decide whether to run the harness through the tunnel or along the left rear seat. The motor and gearbox are currently out so the tunnel route would be a breeze. But with them in, it's a different story.

Frank

[Jeff Alton]

My ECU is mounted on the cockpit side of the firewall. I routed that portion of the harness through a hole I made in the lower corner of the firewall on the passengers side. I have an additional small box that drives my coils and that harnes runs under the package shelf and through the hole the existed for the defroster wires.\

The sensors and wires I needed to run to the front of the car (for gauges and digital dash and fuel pump etc) I routed the factory way through the gromet below the rear seat on the drivers side and then up the side of the rocker and then up through the trunk floor in the pedal area.

Cheers

[Trog]

There appears to be many good solutions to the cable routing. In common is the need to protect the conductors from chaffing and road rash. Ensure you use a grommet whenever you penetrate the firewall to prevent vibration failure.

Other than that, it should all be good.

[dfink]

I must have more wires than everyone else. I believe I counted 27 going from the ECU to the engine bay. This does not count the ones from the wideband. I have 8 plus a spare going to the front. In order to get the wire harness to stay with the engine during a pull mine is made so the large connectors at the ECU can go back through to the engine side. I then have connectors to separate the other wires so the entire engine harness comes out with the engine. I believe I had to have a 2" hole in the firewall to get the connectors to go through. It is half full of wire by the time everything is in. I will make a formed plate that seals off the hole. I guess it could be setup that all the sensor and injector connectors stay with the car when the engine is pulled then the hole would only be as large as the wires. I was going to use a weather pack bulkhead connector but they are only 22 pin I think so I would need to use two of them and they are $60.00 each.

[Trog]

Odd, my firewall penetrations (Qty: 2) are only 1/2" diameter. I installed the connectors on the engine bay side.

[MrPerkles]

Hello Trog
I finally got mine started last weekend but have a query for you and others who contributed to this thread.
My ECU supplier commented that my injector scaling was very high and that this was probably due to low fuel pressure.
I am using a PMO regulator with return and an open looped hose set up,the gauge reads 3 bar then jumps to 4 after a few seconds.So any ideas how it could be starving the Jenvey throttle bodies,fuel lines to short ,unequal ?

How about an update on yours Trog ,dyno readings etc ?

Cherrio

[scarceller]

Fuel starvation at heavy throttle could be a faulty fuel pump that can't deliver enough fuel under hard throttle conditions.

The best way to test this is by placing a fuel gauge where it can be seen while driving (Not Easy but can be done), the fuel pressure must be above 2.5 bar even under WOT conditions.

You can also test Fuel Delivery rate via the specs.

Also a 4 bar pressure seems kind of high. 2.5 - 3.0 is the norm for 3.2L injectors in a stock 3.2L. A pressure higher than 3bar should be investigated. But in a custom EFI setup you could run higher pressure if you wish.

Here are the test specs:

1) at idle FP = 2.0bar
2) at idle disconnect vacuum line from regulator FP = 2.3 - 2.7 bar
3) pitch return line from FPR slowly, be certain pressure goes above 4 bar as you pinch return, do not go any higher than 5 bar, stop once you see 5 bar or so.

Just a thought.

[Trog]

Originally Posted by MrPerkles

Hello Trog
I finally got mine started last weekend but have a query for you and others who contributed to this thread.
My ECU supplier commented that my injector scaling was very high and that this was probably due to low fuel pressure.
I am using a PMO regulator with return and an open looped hose set up,the gauge reads 3 bar then jumps to 4 after a few seconds.So any ideas how it could be starving the Jenvey throttle bodies,fuel lines to short ,unequal ?

How about an update on yours Trog ,dyno readings etc ?

Cherrio

I've set my regulator at 40PSI, (2.75BAR) and it seems to run fine.

What size injectors are you using.. I'm using 26#/hr?

My tuning efforts were placed on hold due to 4 successive snow-storms.

T...

[MrPerkles]

Originally Posted by Trog

I've set my regulator at 40PSI, (2.75BAR) and it seems to run fine.

What size injectors are you using.. I'm using 26#/hr?

My tuning efforts were placed on hold due to 4 successive snow-storms.

T...

Injectors are rated up to 300bhp and shouldnt be the problem I was more worried about fuel line routing and lengths ,the line across the fan housing is dead straight
Its off to the dyno man soon so fingers crossed will be up and running soon,just dont want any daft bills which i could have sorted before it goes into the shop

[tmctguer]

You are an animal !

what a job, and what great documentation !!

[Bart_dood]

Originally Posted by Trog

Best of both worlds:

I remember reading an engine building modding "bible" by david vizard that had a large section on air filters, his testing indicated wire mesh to be the worst of all, no filtration of the small engine wearing particles with the added negative of a major source of flow restriction.

I guess they look nice tho.

[scarceller]

Trog,

I must say this is a great project, nice job!

Will you dyno soon?

[Trog]

Originally Posted by scarceller

Trog,

I must say this is a great project, nice job!

Will you dyno soon?

Probably this spring, when the weather around here improves.

[Trog]

Originally Posted by scarceller

You could achieve some idle control and stability by simply doing it via idle ignition map. I currently do this in my 3.2L Motronic in addition to the ICV.

The idea is to set the ignition to some value that works well at the target idle. For example: say the target idle is 880RPMs and the ignition is set to 0deg. Then in the map you simply advance the ignition if the idle drops below the target and retard if the idle increases above the target.

In my car the target idle is 920RPMs and ignition is set to 5deg BTDC if the idle drops I start advancing the idle as much as 11deg BTDC if it drops to 800RPMs. Then I also retard to -3deg ATDC if it increases to 1000RPMs.

You would be surprised how much you can influence the idle by simply altering the ignition at idle. Adjusting idle in this manner also compensates much faster than a mechanical ICV valve.

I'd hope that any modern day Engine Management System could do this.

Hey Sal,

I wanted to share this with you and the Pelican gang; The TECgt includes a tuning function to adjust for drooping or rising idle RPM. The screen shots below are fairly self explanatory: