Can someone provide the voltage values for checking a MAP sensor? Green wire to ground it reads 1.0 volts koeo and the same at engine idle. At 2500 RPM the voltage increases to 1.5.

I can not find any tables in my Haynes manual that depicts what is an acceptable voltage range.

The Haynes manual for our Saturn (sorry) indicates that 3.8 to 5.5 volts koeo and 2.3 volts less with 10" of vacuum applied. Simple enough.

Thanks for any help.

Russ

 

The MAP sensor on most FoMoCo, (all to my knowledge) emit a frequency related to manifold absolute pressure. Depending on the Barometric pressure and altitude, the signal will be biased, but in general, it should have a ground, supply voltage and the signal at the connector(middle conn). General numbers using a DVM with a Hz function will read in the 150's for a ballpark. Specific numbers will be based on baro and altitude plus intake manifold vacuum.
If they go nutzo, they generally will mess up the idle so it is all over the place.
tom

 

Boy do I feel stupid. What I thought was the MAP sensor is not - so no wonder I was receiving weird information.
Anyway, my Haynes manual indicates that the MAP sensor is on the inner fender well on the passenger side. I can't find it! I did find the octane plug, the EGR relay and the computer test port.

Anyone know where the MAP sensor is indeed on a 90 2.3L 4-cylinder?

Thanks

Russ

 

It was on the firewall, just to the passengers side on my 1989 2.9L. It has an electrical and a vacuum line going to it.

 

I ran across this link cruising the net, don't know if it will help or not, but it looks relevant:

http://www.dainst.com/info/sensors/ford_map.txt

 

Thank you for the information. I set some time aside over the weekend to chase down the MAP for a test (Thanks Rockledge). Alas, I still can not find a MAP sensor. I traced each of the vacuum lines from the source on the intake: one to the fuel pressure regulator, one to the EGR relay, one to the power brake booster, one to the air cleaner and one inside the cab to a vacuum motor on the heater. There are two other vacuum lines that lead from under the intake to the PCV valve and to the charcoal canister. Thats it! I also have not been able to locate the coolant temperature sensor.

This truck was purchased new 3/90 and was not used much between 95 -99. Ever since we have had pinging problems. Some have been resolved - faulty EGR relay. Now it will only ping on a very hot day and under partial throttle.

Any ideas? Thanks for whatever help can be provided.

Russ

 

I looked in my 1989 Ford EVTM manual and it says the MAP is at the righthand side of the dash panel but no picture of it and the rest of my 1989 books are home. The ECT should be just above and slightly behind the oil filter, remember it has two wires not one.

 

Thank you Ken. I took an opportunity today to look under the dashboard and found two sensors neither of which have a vacuum line attached: One is a E97T-6C625 BA - whatever that is and the other is a E9EB-10B924-AA whatever that is. Sorry about the trifocals and some of these characters/numerals were very small.

I will try and get the truck up on a lift and look for the ECT near the oil filter. I ran my hand around from the top and did not feel anything. Is there a test procedure for the ECT?

Thanks again for any guidance.

Russ

 

Here is another link that might help:

MANIFOLD ABSOLUTE PRESSURE SENSOR TESTING & INSTALLING

It includes a sketch of the Ford MAP (Fig. 5), as well as a test procedure.

ON EDIT: At the risk of sounding really dumb, which I am about this type of motor, is it a definite that the '90 2.3L has a MAP? Sequential Fuel Injection (SFI) vehicles use a Mass Air Flow (MAF) sensor while Multiport Fuel Injection (MFI) vehicles are equipped with a MAP sensor, isn' that how it goes? If so, then the question would be, does the '90 version of the 2.3L have SFI instead of MFI? Just a thought on my part.

 

The ECT can be tested by measuring the resistance at various temperatures.

Thats a very good point rockledge, my book is a 1989, I don't have a 1990.

Do you have a MAF rangerruss, it would be between the air box and TB.

 

Thanks Ken and Rockledge. The truck may very well not have a MAP sensor. Now it is my turn to sound dumb: How do I tell the difference between Sequential and Multi-port Fuel Injection systems? The decal under the hood only says that the truck is equipped with EEC IV, EFI and DIS systems. There is a throttle body and a fuel rail which feeds the four fuel injectors. I did check the TPS today - .85 volts at idle and 4.8 volts full throttle. Seems to be within range. I will have to jack it up to check the ECT and O2 sensors. Will try and do that tomorrow evening.

Again, thank you profusely for all of your help and patience.

Russ

 

Russ, much easier for you to try and find the MAF rather than figure out the type of FI system you have. If you have an MAF then you don't have a MAP.

Here is a link to an online catalog from a company that offers replacement MAFs for later model vehicles. It may shed some light on the issue. If you notice on page 3 of the catalog the company does offer a replacement MAF for the '90 2.3L Ranger engine. Also, if you go to last page of the catalog you can view several pictures of MAFs which will help you get a better idea of what you are looking for.

Link to MAF Catalog

Hope it helps!

 

Thank you again for the input. The truck does indeed have a MAF sensor. It is attached to the air cleaner housing and is between it and the hose to the throttle body for the fuel injection. So, that is probably why I cant find the MAP sensor. ]

I still plan to get voltage readings from the ECT and O2 sensors tonight. Something somewhere is causing this spark knock when the engine is hot and at cruising speed. ugh!@#$%^&* keep at it until I find it.

Thanks again this will be a great story when all is said and done.

Russ

 

Well it's good that we solved that riddle. Keep us posted on your progress!

P.S. I'm not sure how the MAF is configured on your '90 2.3L, and whether or not is capable of being cleaned, but cleaning the MAF sensor is one of the things people do to help get rid of the pinging, at least on the Ford 3.0Ls and 4.0Ls. Here is a link to another thread on the subject of Throttle Body/MAF cleaning:

https://www.ford-trucks.com/forums/s...hreadid=116328

Like I said, I'm not sure if it would apply to your 2.3L setup or not.

 

Russ, do you have a K&N (or other oiled-type) air filter in the truck? I have read lots of posts about the oil from these coating the MAF and causing all kinds of problems. Just a thought.