Need help with a charging system problem

[Alan]

Okay, I know we just talked about Toyota pickup's with the 22r engine. :?

My son has a 1990 Toyota pickup with the 22R and the other day his check engine light came on. We check his charging system with my meter, zero charge. He went home and changed the Alternator, still no charge. He is now on his third new Alternator and no charge. Here's what we know;

3 new alternators
New belt, it's tight.
Internal regulator in the alternator
The wiring is good in the plug coming out of the alternator, the rest of their journey???
Battery is good
As far as I know there is one inline fuse, it is good

Could this be the luck of 3 bad alternators from 2different part houses?


Any help?

Thanks,
Alan

 

[dun]

I doubt it, sounds like something else is wrong in the charging system

 

[skyhightree1]

Check the charging cable that could be damaged or frayed. also some vehicles have alternator relays or fuses... take alternator out and have alternator checked at parts store.

 

[Kingfisher]

I'm cOnfused...you say the check engine light is on? Did you scan it? What codes are present?

 

[skyhightree1]

I'm cOnfused...you say the check engine light is on? Did you scan it? What codes are present?

King in 1996 or 1997 the auto industry came out with the standardized obd all scanner tool. They can't scan a 1990.

 

[saltbranch]

You should be able to have the Altenators tested at the auto parts store to see if they are putting out. If they are you can chase it down from there. Do you know if the truck has a fusible link in the harness going to the alt.? IT will look like a regular piece of wire but is like a fuse, hard to tell when its burned up.

 

[Alan]

I'm cOnfused...you say the check engine light is on? Did you scan it? What codes are present?

King in 1996 or 1997 the auto industry came out with the standardized obd all scanner tool. They can't scan a 1990.

Thank you Sky! Yes, this is years before the OBD system, still old school, which is good in some ways but not in others.

 

[saltbranch]

Alan are any of the brake warning lights on?

 

[Alan]

You should be able to have the Altenators tested at the auto parts store to see if they are putting out. If they are you can chase it down from there. Do you know if the truck has a fusible link in the harness going to the alt.? IT will look like a regular piece of wire but is like a fuse, hard to tell when its burned up.

I know what you mean, two of the alternators where benched tested at the buyers place, he paid $60 for them(got a refund). But they benched good, but they said all alts always bench good and one guy said he went through 3 to get a good one. That was the good benched tested ones, on the third he went to another parts shop and paid $120 for an alt it benched good, but bad in his truck, they test the system in his truck and it still goes to the alt (alternator). He is putting in the fourth as I type ....
We'll see. He did get a diagragm and there is two in line fuses both are good no relays. :?


Thanks for your help all! Any other help is welcome!

Alan

 

[Kingfisher]

When you go "key on" does the light on the dash illuminate?

 

[saltbranch]

They benched good and do not put out when installed. Then the alternator is not being excited to produce power. There has got to be a wire or something that excites the alt. to produce power.
I had the same problem on my sons 1978 Bronco, it was a fusible link that had burned. I did not think American Iron used the fusible links back then...anyways I replaced with an inline fuse link and we were back in business...that was about a 3 week cursing venture.
If the alt.s are bench testing ok and get in the truck and no juice, then there is something not telling the alt. to produce power. They do make a General motors one wire conversion alt. that you can swap in. It uses RPM to excite and start the alt charging. At startup, bump the throttle and it excites alt to charge,

 

[Alan]

They benched good and do not put out when installed. Then the alternator is not being excited to produce power. There has got to be a wire or something that excites the alt. to produce power.
I had the same problem on my sons 1978 Bronco, it was a fusible link that had burned. I did not think American Iron used the fusible links back then...anyways I replaced with an inline fuse link and we were back in business...that was about a 3 week cursing venture.
If the alt.s are bench testing ok and get in the truck and no juice, then there is something not telling the alt. to produce power. They do make a General motors one wire conversion alt. that you can swap in. It uses RPM to excite and start the alt charging. At startup, bump the throttle and it excites alt to charge,

Thank you! Good info, I'll talk to my son tomorrow about it. BTW he's 28 and a very good auto wrench! With all of your help we should get this figured out. Although if it's electrical it may be on him ..... I'm lousy with electrical. :?

 

[Alan]

When you go "key on" does the light on the dash illuminate?

We'll find out in the morning, he's stressed and lives 30 miles away, but a very good question. BTW, when he's stressed he's like me, he sends it to any ear that will listen. :lol:

 

[greybeard]

That's actually OBD1, and yes, it can be scanned, but the scanners for OBD1 were individual brand (GM, Ford, Toyota etc) specific--not universal. Different makes used different kinds of code readers and codes. (My 84 Fieros also use OBD1, and I manually check those codes all the time myself) Scanners for those older ones are now hard to find, but you can check the codes yourself. You can check the codes, by jumping out the diagnostic terminals, turning key to "on" and watching the number of flashes the check engine light makes.


Toyota 1990-1995 vehicles obd1 code retrieval
When the check engine light shows up in your 1990-95 Toyota vehicle, the quickest way to get the code is to access the diagnostic connector in the engine compartment ( usually sitting in the fender) or by the kick panel under the dash board in the passenger side. Connect a jumper wire between terminals TE1 and E1 terminals and by turning the key on, it will start flashing the codes in your dash. On Tercel and MR2, use the jumper wire between terminals T and E1 instead.

If there are no codes, the check engine light will flash 2 times per second CONSTANTLY with no patterns or pauses. If there are any codes, it will be shown in 2 digits codes. Example: code 24 is shown as 2 flashes, a pause followed by 4 flashes. If there are mode codes, the next one will transmitted after 2.5 seconds. (One some models, codes are displayed in one digit code only and the difference is the codes are displayed with 4.5 seconds delay between codes). When finished reading the codes, turn the key off and remove the jumper wire.




Here are the common codes for Toyota vehicles 1988-95:

Code 11 Momentary interruption in power supply to ECU (electronic control unit or computer) up to 1991
Code 12 Engine revolution signal missing
Code 13 Rpm signal to ecu missing above 1000 rpm
Code 14 Igniter signal to ecu missing
Code 16 A/T control signal missing from ecu
Code 21 Main oxygen sensor signal fault
Code 22 Water temperature sensor circuit fault
Code 23 and 24 Intake air temperature signal fault
Code 25 Air/fuel ratio LEAN
Code 26 Air/fuel ratio RICH
Code 27 Sub-oxygen sensor signal or heater circuit fault
Code 28 No.2 oxygen sensor/heater signal fault
Code 31 and 32 Air flow meter circuit or Vacuum sensor signal fault
Code 34 and 36 Turbo-charging pressure signal fault
Code 35 Altitude compensation sensor signal fault
Code 41 Throttle position circuit fault
Code 42 Vehicle speed sensor circuit
Code 43 No starter signal to the ecu
Code 51 AC signal on; DL contact off (in trany shifter with diagnostic connector jumped)
Code 52, 53 and 55 Knock sensor fault
Code 71 EGR system malfunction
Code 72 Fuel cut solenoid signal fault
Code 78 Fuel pump control signal fault
Code 81, 83, 84 and 85 TCM communication fault

For 1990 Toyota Truck, the specific procedure and codes are:
http://www.justanswer.com/toyota/21ek4- ... -22re.html

 

[greybeard]

I don't see anything in those fault codes related to "no charging" or "low Voltage" conditions. But that's not surprising. It's only recently that mechanical and electrical faults have shown up in diagnostics. Early diagnostics focused only on emission related problems. An electric fuel pump could be out, or the alt not work and there was no code for "no or low voltage" or "No or low fuel pressure". That was the whole purpose of the federally mandated diagnostics on any vehicle sold in the US--to make it easier for the vehicle owner to know when the vehicle wasn't up to snuff as far as emissions went--for the life of the vehicle. They mostly just cheked sensors, tho some mid 90s GM products did have a "High voltage" code----no "low voltage" tho.
If I remember correctly, there is a CHG fuse under the dash on Toyota trucks. If that fuse is bad, the Alt will not put out over 1.5 Vdc.
Check the fuse holder as well--they tend to not make good contacts on units this old.

 

[bbirder]

I Think Saltbranch hit the nail on the head!

 

[ALACOWMAN]

fuse are alternator relay

 

[Alan]

He got it fixed, it was the relay.

Dammm boy is as hard headed as me, he got so frustrated I just backed away and said good luck :tiphat: He stuck with it and got it figured out.

Thanks all for the help.

Alan