Engine Car Wont Rev Past 4/4.5k

That sucks but hopefully they find a quick and easy solution to the problem.
At $99 an hour for diagnostics I hope its quick too lol. My whole family has had their cars worked on by this shop at one time or another and they have always been really fair and honest so I do trust them. I have a feeling its something very stupid and small that probably would have only cost me $20 or so but I couldn't figure out.
 
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still haven't heard anything back from the shop, which i take as a bad thing because the car got there Wednesday and he said he would have all day yesterday and today to look at it and would call me as soon as he started getting somewhere with it. anyway when you guys mentioned the coolant temp sensor i didnt think much of it but would a malfunctioning sensor cause the computer to change air fuel maps/ affect timing? i have been reading a few different peoples threads and a few had weird issues due to bad ECT sensors. i didnt have any codes related to it but if the guys shop had 2 full days and cant come up with anything it probably cant hurt for me to keep thinking.
 
Trust me a bad ECT sensor will cause your car to run real rich or real lean once the engine is warm. And sometimes it will not even send a code and your car will run like crap.
 
Trust me a bad ECT sensor will cause your car to run real rich or real lean once the engine is warm. And sometimes it will not even send a code and your car will run like crap.
Well I'll give the guy a little more time to mess with the car and see what all he finds I guess im just impatient lol. I had the car for like 2 months now trying to figure this out and cant so i cant expect him to find the problem in 20 mins. This is the only car I have ever given up on and farmed out for someone els to look at so im a little out of my element.
 
Well I'll give the guy a little more time to mess with the car and see what all he finds I guess im just impatient lol. I had the car for like 2 months now trying to figure this out and cant so i cant expect him to find the problem in 20 mins. This is the only car I have ever given up on and farmed out for someone els to look at so im a little out of my element.
If the don't have the ECT temp to voltage map, they will never find a marginal ECT....


Code 51 Engine Coolant Temperature (ECT) sensor signal is/was too high -
Possible bad ECT sensor, or wiring. Possible missing signal ground – black/wire wire broken or bad connection. With the power off, measure the resistance between the black/white wire and battery ground. You should see less than 1 ohm. Check the same black /white wire on the TPS and MAP sensor. More than 1 ohm there and the wire is probably broken in the harness between the engine and the computer. The 10 pin connectors pass the black/white wire back to the computer, and can cause problems.

The ECT sensor is not the same as the temp sender for the temp gauge. It is located in the front part of the tubing that feeds coolant to the heater. It has two wires connected to it.

Pin 7 on the computer - ECT signal in. at 176 degrees F it should be .80 volts

Voltages may be measured across the ECT by probing the connector from the rear.
Use care in doing it so that you don't damage the wiring or connector.

50 degrees F = 3.52 v
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
212 degrees F = .47 v
230 degrees F = .36 v
248 degrees F = .28 v

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor disconnected.

50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
212 degrees F = 2.07 K ohms
230 degrees F = 1.55 K ohms
248 degrees F = 1.18 k ohms

Diagram courtesy of Tmoss & Stang&2birds

88-91_5.0_EEC_Wiring_Diagram.gif


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/

http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif
 
So to make sure im understanding correctly the ECT, TPS, and, MAP all share a common ground/ black/white wire? If so it would make sense if I have a broken wire or bad connection at the 10 pins somewhere because I have that TPS code. Now I wish I still had the car at my house so i could check right now lol. Is there any company that makes a plug and play repro harness? Mine is old and has had its number of hacked stuff anyway. I know late model has the injector harness and 02 harnesses but does anyone make a complete one?
 
So to make sure im understanding correctly the ECT, TPS, and, MAP all share a common ground/ black/white wire? If so it would make sense if I have a broken wire or bad connection at the 10 pins somewhere because I have that TPS code. Now I wish I still had the car at my house so i could check right now lol. Is there any company that makes a plug and play repro harness? Mine is old and has had its number of hacked stuff anyway. I know late model has the injector harness and 02 harnesses but does anyone make a complete one?
The engine mounted sensors and MAP all share the black/white wire (pin 46 on the computer) as a common signal ground. The 10 pin connectors can sometimes cause flaky problems that are hard to find.

fuel-injector-wiring-harness-sensors-for-5-0-mustang-gif.49009



See the graphic for the 10 pin connector circuit layout.
salt-pepper-10-pin-connectors-65-jpg.68512
 
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i got a call from the shop today. he found that at idle the car maintains a solid 42psi fuel pressure and when under load (the one thing i didnt have the tools to check) it drops to about 15 psi. so im suspecting the new pump i put in is junk. im going to call late model today and see what kind of warranty they have on their pumps and how soon they can get me a new one. the one i bought is a 155lph walbro anyone have any recommendation on a better one? i've used walbros lots of times in forced induction Honda builds and they have never given me an issue.
 
so im a little disappointed, latemodel will take the pump back but i have to pay return shipping and they dont have 155lph walbros in stock. i ended up ordering a 190lph walbro kit for $10 more. regardless im hoping that this will finally fix the car. I also wanted to order a new pump hanger but they were out of stock.
 
Had a little time today so I drained all the old gas and pulled the pump out of the tank. At first the pump was making the normal wine and then as it continued to pump half a tank of gas out into gas cans it got pretty quiet. Im a little concerned about the condition of the sock and the crud in the bottom of a tank I cleaned less than 150 miles ago. Im almost considering getting a new tank so I wont have to do this again. You can also see why I wanted to replace the hanger aswell.
20140821_151345.jpg
 
Bring it to a local radiator shop and see if they can hot tank it for you.
been there done that they want $20 less than i could get a brand new tank for so i just cleaned it the last time around and thought i got it pretty clean but apparently i was mistaken. anyone have the stangnet discount codes for late model and American muscle im trying to decide where i want to order stuff and late model takes minimum 6 days to get me parts but American muscle can get me stuff in about 2.
 
been there done that they want $20 less than i could get a brand new tank for so i just cleaned it the last time around and thought i got it pretty clean but apparently i was mistaken. anyone have the stangnet discount codes for late model and American muscle im trying to decide where i want to order stuff and late model takes minimum 6 days to get me parts but American muscle can get me stuff in about 2.

email them for the code and they will send it to you . They both price match
 
Ok guys this time I think I can confidently say the problem is fixed. New tank, pump, sending unit, and hanger went in today and so far all seems well. I still get a little spitting here and there around 4500rpm but the car is a night and day difference. Im thinking the plugs are probably shot due to the car running down to 10psi fuel pressure so im going to grab another set and see where that gets me. Hopefully now I can concentrate on fun mods like suspension and a head and intake swap. Thanks again for all the info and help but now i need to go to the car wash so I can drive the car tomorrow lol.