• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

1991 Volvo 240 Wagon SE with B230FT and M46 swap will not pass (colorado)emissions.

91FrankenWagen

New member
Joined
Dec 4, 2021
Location
Denver, CO
Swapped the engine from a '91 740T into my '91 240. LH 2.2 Fuel and EZK 117K Ign. modules are from an '89 740T, all conversion components are from the '89. Put an M46 from another '89 740T in, using the cross-member, clutch and shifter parts from an '82 240. Used the intermediate shaft from the '91 240, then bought a new '88 240 distributor with the hall effect sensor.

Everything went together pretty smoothly, wiring everything to the proper pins was a bit of a hassle, but not too bad.

Went to the emissions here in Denver, CO and failed. HC was 3.9 grams per miles, allowed is 1.5. CO was 75/20.

Replaced with new: Spark plugs, Ign. wires, O2S. Checked idle timing, set to 12 BTDC. After O2S replaced, checked voltage on O2S green wire. I could not get it adjusted to the .6-.7V using the MAF screw, O2S disconnected. Swapped MAF for another used one out of an '89 740T. Was able to adjust to .6V, plugged back in, O2S fluctuated from ~.2 to ~.8V.

Took back to smog facility, HC was 2.8/1.5, CO 44/20 GPM. "Getting closer" I thought.

Went back to the garage and made a MAF-to-Throttle adapter to bypass boost from turbo. With this redneck turbo delete, I went back. HC 2.7/1.5, CO 47/20 GPM. Very little difference.

I will attach a pic of the three test results, with the data graphs. It seems as though the HC and CO levels spike after the dyno operator lets off the throttle to maintain speed. The CAT is probably OEM to the '89 740T, but it isn't clogged or stinking yet. I was hoping to get this thing registered before they put commiefornia smog regs in place Jan 2022. If I have to put a new cat on, it is what it is, but I want to make sure I'm not missing something completely obvious. Any input is appreciated

https://ibb.co/KFCV1M1
https://ibb.co/2Ynj3J2
 
Last edited:
Take the air filter out of the housing and knock a couple pin holes in the exhaust just before the muffler.

This is professional advice. I'm on the internet.
 
thought about the exhaust holes, I may try that out. the air filter is a cone on the MAF, so I don't know how much taking it off will do.

I re-read the B230FT conversion article and realized that I had missed the part about the ballast resistor for the low impedance injectors on the 740T. :oops: Serendipitously, there happened to be a '96 850T in the junkyard about 3 miles away, so I went and grabbed those injectors and slapped them in the 240T. I won't know how much of a difference it'll make until I tune the MAF, Ign. timing, and go back to the I/M dyno, but it did solve a stutter the car had under light throttle! :cool: I already needed to go through my O/D, but at least I might not find chunks...
 
1.47 out of 1.5 HC (Close, but it counts. Not bad for a 32 year old catalytic converter) and 10.20 out of 20 CO After the test, I realized I had forgotten to re-calibrate the AMM, so when I set it, it was at ~550 Ohms. My I/M numbers probably could have been better had I set it at the factory 380 ohms... It actually runs a bit better at the lower Ohms. Timing is set at 12 BTDC, and Idle manually set at 750. (my Idle air valve is toast, and I haven't sourced a new one.)
 
I don't know a whole lot about the LH 2.2, but it makes sense why it was pegging the fuel out of boost with the low impedance injectors in the high impedance system. I've had trouble finding the description of these symptoms as it relates to adapting the 740T powertrain to the 240 wiring... The green top injectors out of the 740T were 2.5 Ohms each, whereas the orange/brownish injectors from the 850T were each ~14.7 Ohms. I've read that the volume of the 850T Injectors is slightly higher than 740T injectors, so with the factory 740T AMM, it would make sense that I would have to dial it down a bit. Looking for the 006 3" AMM, but new is pricey, cheap knock offs are not to be trusted, and used seems to be getting pretty rare.
 
Check fuel pressure and regulator. It can be stuck or leaking.

I didn't mean to ignore this reply. I had to replace the FPR when the engine was in the old car, because it had been sucking 8-year-old gas into the throttle body, rotting out everything in its path. It is an aftermarket, but my fuel pressure numbers are right on the money. It has the 740T main pump in it, and I have the tank pump, but I've yet to swap it out.
 
I re-read the B230FT conversion article and realized that I had missed the part about the ballast resistor for the low impedance injectors on the 740T. :oops: Serendipitously, there happened to be a '96 850T in the junkyard about 3 miles away, so I went and grabbed those injectors

Ok, so low impedance injectors were accidentally used without the needed ballast resistor. Was the emission failure attributed to THIS or the MAF setting? If it was THIS, then did the injectors run richer without the resistor?
Dave B
 
Running low impedance injectors without the ballast resistor usually fries the injector driver power transistor in the ECU, so the OP got really lucky. (If needed in the future, I think there are still transistor replacement instructions somewhere on ipdown.)

Assuming that the power transistor wasn't damaged, I'd expect some mis-matched fueling compared to running with the resistor pack. The higher injector drive currents from low-impedance non-resistor pack will cause the injector to slam open and closed more quickly, and to be a little more responsive at idle/low pulse widths. Probably not enough difference by itself to cause the off-the-chart emissions graphs.
 
Sorry for the delayed reply. I did get very lucky that my ECU did not fry. I didn't change anything with the MAF setting between failing with the 2.5 ohm injectors and passing with the 14.7 ohm injectors. I attributed the smog test failure to the incorrect injectors.
 
Probably not enough difference by itself to cause the off-the-chart emissions graphs.

I didn't think it would cause it either, but unless the excess current draw was making other parts of the computer malfunction, that's the only reason I could think of...
 
Back
Top