TD Max Booster Controller - throws codes

[Iain]

Well here is my issue. I installed a TD Max Boost Controller on my truck. 1994 with 270,000 km on it (approx 168,000 miles). It runs well for its age! I did not put a boost gauge or a pyrometer on her yet, so I figured I would leave the controller on with its factory settings 9supposed to be 2-3 lbs of boost). I noticed a bit of a difference in power but nothing to write home about. At this point the truck threw no codes.

I got adventurous and turn the screw on it 1/2 turn clockwise (increased boost), turbo picked up a lot and no immediate concerns or problems. The other day I was driving on the highway with the cruise on at 70mph and the SES light came on and kicked off the cruise. After a few seconds it went away. It did this a number of times and only seemed to be when the truck was going down a gentle slope and the throttle was starting to back off a bit. Under load or fully unloaded throttle poisiton the SES would not come on. I could drive without the cruise and while the engine light came on it did not affect the truck, it ran fine, still had power and ran smooth. I checked the codes and it came up with the following:

36 - Injection Pulse Width Error - Response time too long
78 - Waste Gate Solinoid

All the vacuum lines are good and the vacuum pump is O.K. I thought the Boost Controller may have had something to do with this, so I turned the screw 1/4 counter-clockwise - decreased the boost (so overall I have 1/4 turn increase over the factory setting). Took it out for a day drive today and the SES light came on only once all day and then went out. Same codes.

Does the computer on a 1994 not like the increase in boost however slight? The truck runs great other than that and when the SES comes on, there is no change in power, pitch, no stuttering, you jump back on the pedal and away she goes. As I do not have a boost guage I could not tell what it is putting out for boost (I know....I will put one in....soon).
Thanks for the advice Guys!

Iain

[Scrufdog]

any computer doesnt like much more boost than stock, this is why you get a boost gauge before you get a manual boost controller.

At this point you either need to get some sort of boost gauge, and keep the max boost at around 8 psi.

[gmctd]

You really need Boost and EGT gages, Iain - increased Boost means increased Intake Air Temperature with no charge-air cooler, which means higher EGT's.

When you alter PCM's sense of what's happening, chances of engine damage increase dramatically, particularly when you also have no sense of what's happening - those gages are the most important addition to your truck, along with the '97 cooling upgrade.

If both DTC's reoccur after you've cleared them, you might check your batteries and power and ground terminations, as well as the engine harness connectors - DTC 36, which also cuts Cruise, can mean low voltage, or failing Inj Pump, and can cause Limp Mode.

[DennisG01]

I know....I will put one in....soon.

Iain


In the meantime, since it's happening when you're light on the throttle, I doubt it's because of the boost fooler. The wastegate solenoid has a tendency of hanging up which will then throw a code. If it's been in there for more than a few years, try replacing it - it's about a $25 part - or you could also try squirting some WD-40 into the vac line that's attached to the actual wastegate to try and free up the solenoid. This may not be the problem, but it is a likely culprit.

[Kennedy]

Lots of good suggestions here.

Gauges mandatory

WD40 in vac line to help lube system


As for the code what is happening is that the ECM sees too little boost at that speed.

From there I'll point out my note on the item listing on the web store:

"While this unit works on all model years, it is particularly effective on 1996 up trucks with HD "F" engine programming. It is my suggestion that 94-5 trucks take advantage of the TD-Max Performance Chip Prior to installing this unit as it will likely be unnecessary to ad the boost control with the proper chip calibration. Use on the 94-5 trucks and 96+ LD "S" engines may require a second controller on the firewall mounted MAP sensor to avoid an aggravated DTC 78 (wastegate solenoid) fault code." - JK

[Iain]

All great points, thanks alot guys! Chips and guages are on the shopping list.

Iain