Car is Down 50hp...Suggestions Welcome

[Swarzkopf]

Went to the track last night looking for 12s.

So as to my runs....I gained.8 on my ET and lost 7mph. At this point, I have no idea why. My best run last night was the first one, with a 1.9 second 60', which felt strong, followed by a 14.1 second 1/4 mile at 98mph. WHAT THE ****. I didn't **** anything up, didn't overheat, don't hear any tell-tale noises from my block, and the car in general still accelerates and drives normally. Hell, it still feels as fast as it did when I ran 13.3@105, it just isn't. I made three runs, 14.1@98, then 14.2@96, then 14.4@96.

As I said, there are no tell tale signs. The car is running smoothly, not burning oil or coolant, not making any goofy noises, ect. According to the MustangWorks calculator, I'm down 50hp.

Here are the changes made to the car between last time at the track (13.3@105 and this time 14.1@9 :

160* Thermostat installed
New lightweight Summit seats installed, old seats yanked
Sound deadening and carpeting removed from interior

That's it...nothing I can see that would take away 50hp.

I tested my nitrous system this morning and it's spraying as it should. There is a slight leak where the injection nozzle meets the intake tube, but I don't think it's a 50hp leak.

Also, my coolant temperature sensor is ****ed and the cooling fan isn't working as it should, but, the car is NOT overheating and didn't overheat at the track. It ran cool as normal. Again, I don't think that this would take away 50 horsepower even if it were a factor (which it's not).

This weekend I'll check it over good, starting with the plugs, then the distributor, then the fuel pressure...at this point, I'm thinking one or two cylinders are not getting either fuel or spark.

Wish me luck. Any suggestions are welcome and appeciated.

 

[CManT1914]

If the ECT is not working properly, it CAN cause problems. Like you said, I wouldn't think it would cause such a drastic change, but did you factor in weather conditions? When I went December I ran 14.1's @ 99. When I went back in February (hot as hell that night) I ran 14.5's @ 96 or so. Weather effects power BIG time!

 

[Chythar]

The ECT feeds the computer and tells it how hot the engine is. The computer then alters the fuel curves to match. If the ECT is telling the computer that tne engine is close to overheating (even if it isn't), the computer will richen the fuel curve to cool off the engine. This makes for an inefficient fuel burn and less horsepower. I'd suggest replacing both temp sensors - the ECT and the CTS. That may get your 50hp back.

 

[Swarzkopf]

Yeah, I should have posted that. Both times at the track it was ~75, clear and sunny. Almost identical weather.

The ECT can cause power problems? I'll be replacing it then. I didn't think it would be a factor- what does it do exactly?Cause increased fuel injector pulse?

Thanks for the feedback. Keep it coming guys.

 

[Swarzkopf]

Missed your post Chythar. Thanks!

 

[CManT1914]

Yeah, I should have posted that. Both times at the track it was ~75, clear and sunny. Almost identical weather.

The ECT can cause power problems? I'll be replacing it then. I didn't think it would be a factor- what does it do exactly?Cause increased fuel injector pulse?

Thanks for the feedback. Keep it coming guys.

No need to replace the ECT yet, (unless you're sure it's messed up). Have you done an ohms test to see if it's still in spec? Make sure the connections aren't dirty either. Sometimes if a sensor just gets dirty it can fawk everything up. Good luck

 

[Swarzkopf]

I'm sure it's messed up. My cooling fan does not kick on when engine temp rises. With the 160* thermostat, this isn't a problem as the engine temp never gets that high, but I noticed it before swapping from the factory 192* unit. The cooling fan does kick on when the AC is on. As per other Stangnetters advice, this points to a faulty ECT.

Thanks, I'll keep you guys posted.

 

[Swarzkopf]

I'm also thinking perhaps I have an injector frozen open...I do run high fuel pressure. Besides looking at the plug for unburnt fuel, is there any other way to determine if an injector is frozen?

Keep in mind, until I actually start working on the car, I'm just throwing things out there.

 

[dstanggt50]

I'm also thinking perhaps I have an injector frozen open...I do run high fuel pressure. Besides looking at the plug for unburnt fuel, is there any other way to determine if an injector is frozen?

Keep in mind, until I actually start working on the car, I'm just throwing things out there.

I know this test will work for a faulty injector, I would assume it would work for one thats stuck open, you could do the cylinder balance test where it shuts off each individual inj one at a time, and your supposed to look at the rpms and see if it drops by a couple of hundred when each is shut off. I would assume the ect and cts would be good to replace, and maybe clean you maf or check your voltage to your maf. Maybe also do a compression check also.

 

[Swarzkopf]

dstanggt50, thanks for the info.

know this test will work for a faulty injector, I would assume it would work for one thats stuck open, you could do the cylinder balance test where it shuts off each individual inj one at a time, and your supposed to look at the rpms and see if it drops by a couple of hundred when each is shut off.

I'm not familiar with this test. Is it outlined in Hayne's? I'll look into it for sure.

and maybe clean you maf or check your voltage to your maf.

The MAF is clean and I'd hope not fried, as it's a Pro-M unit I just intalled in August or so of last year.

Maybe also do a compression check also.

This is going to be my last resort. I really hope I've got a good motor still. I'd like to think that I'd be burning oil or coolant if I had bad compression or overheating if it were a headgasket.

 

[nmcgrawj]

what was that injector test exactly?

 

[dstanggt50]

I use a scan tool and do the koer test. after the test is done, it instructs me to blip the throttle 1/4-1/2 down, the car will raise the rpms to about 1600 or so, then after a few seconds it starts shutting down each injector and the way you test it is to see if the rpms drop a couple of hundred, if it doesn't , than when the injector is turned off, your car doesn't run any different, it is a sign that you have a faulty injector. If you don't have a scanner, you can pick one up pretty cheap at an autoparts store, mine was only around 30, for ford only eec iv, works on mustangs and any other car with that family of processors. Also, I think that a bad headgasket will affect your compression, maybe do the test just to see what your #'s are, might be a headgasket.

 

[Swarzkopf]

Seems the problem was the nitrous leak.

A guy on my forum suggested that if the nitrous is leaking, the NMU is still giving the engine fuel to match a 125 shot, even if it's only getting a ~110 or whatever shot, causing a very rich condition.

I fixed the leak today, and test it out against a BMW M3. I beat him pretty solidly on the 100 shot, so I assume it's fixed and the car is back to it's normal self.

 

[oohsoobad2]

If you are talking about your runs on the bottle, then there are other factors to consider as well. I also run a Zex nitrous kit and bottle pressure is very important to how the car performs. If your previous ET's were with a fresh bottle and now your running a bottle that 3/4 full, there will be a big differance it how it runs..