Low power/MPG on 1990 166hp 7.3 IDI

[riotwarrior]

Factory LOW HP is a high altitude engine, less O2 at high elevation and same amount of fuel means black smoke and ...and HIGH EGT's

In all likely hood you've got a worn pump and injectors as well.


If you dig around my threads, you may find a tip or two on timing, go to advanced type TECH 101 choose thread titles and my username, there are about 3 or 4 threads, showing marks and all kinds of info for you.

Time at 2000 RPM use timing tape if you have a non adjustable timing light and yer golden!

Hope that helps

 

[OLDBULL8]

you have an ih based engine not a ford based engine, due to different gearing available

He has a Ford 1990 F350. Not an IH S series.

Truck is California 1990 F350 dually extended cab 7.3 166hp diesel, 4:10 Sterling 10.25 rear end, E4OD trans

Some tags on the engine designate two HP ratings.

He has the original IP on it (125K miles) and the injectors have been replaced at 70K miles. None of us know what injectors or IP he has.

Until he sets the timing at 8.5 to 9 BTDC and turns up the fuel a little, then he can make an assesment as to how the engine will react, if it's not better, then he can start spending money, replace the IP and injectors.

I dynod the truck yesterday, and it made 129 rwhp at 3200 rpm. Again, this was after advancing the timing to 6-7 degrees BTDC.

Advancing the timing to 8.5 to 9 and a little more fuel may increase the HP. If the 3200 RPM was WOT, if it was then the Gov. was limiting it to that.

To give him the right answers, we have to know what injectors and model IP he has. But I would say try the timing and fuel first. Then go from there.

Edit: Al; not a retort to your post, I just type slow. I agree with you.

 

[kas83]

That's about what my uncle's 92 would do in Denver, except at about 3000 rpm. My 90 would do right at 110hp @ 3450 rpm and my cousins 6.9 would do 95 @ 3300.

Come to think of it, I don't think his 92 would turn much over 3200, where as the other trucks would pull to 3600 with reman low altitude pumps. Maybe the governor was set lower on high altitude pumps too?

Sent from my XT1060 using Tapatalk

 

[metermatch]

I don't think I was limited to 3200 rpm, or hit the governor. I just didn't want to over rev the motor. I believe the dyno operator revved the motor out to about 3600 rpm because when he floored it, it downshifted to 2nd gear before reving up, and I think power actually went to 131 hp at the wheels.

I am going to work on advancing the timing the full 9 degrees.

A previous post indicated a burned out glow plug shortly after advancing the timing. Is there a possibility of damaging or breaking a glow plug from advancing the timing?

I have noticed that on cold starting at about 45-50 degrees, it has more of a rattle after I advanced it to 6-7 degrees, compared to the stock setting of about 3 degrees.

Thank You for the advice.

Jeff

 

[icanfixall]

Stock setting for timing are 8.5 degrees advance. anything less is leaving hp and fuel mileage on the deck top. Bring it up to 9.0 degrees advance and try that. Its felt that 10.5 and more advance will ruin the glow plugs.

 

[metermatch]

Are there any known issues with the timing marks moving or slop in the gears causing less than accurate timing readings?

It is a known problem with, for example, some domestic V8 gas engine dampers that when they get old, the rubber part will allow the outer part of the damper to slide a bit, making the timing mark inaccurate. I have always checked the timing mark on the damper for accuracy when building an engine.

A 2 degree difference between correct (8.5 degrees) and 10.5 degrees doesn't leave much room for error.

Thank You,

Jeff