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Full Version: New-to-Me 74 1.8l_Where to start on electrical issues
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rcautox
Hi all,

I've been scouring 914 world for help on getting a new-to-me '74 1.8l running. I've reviewed Auto Atlanta's informative video on the 914 fuse & wiring and I think I follow the gist but may have missed things. I've also studied the simplified diagrams on Pelican Parts which have been helpful to understand the 914 layout.

What I've done:
1. new battery
2. new ground strap straight to the transmission bolt in the rear of the engine bay
3. cleaned battery connections
4. cleaned the fuse panel

When I turn the key the only thing I can see working is the marker lights and the clock. So no fuel pump, no start, etc.

Can you all point me to a few areas to tackle first to determine the culprit(s)?
SteveL
Seat Belt Interlock ?

Van B
Carbs, FI?
Dave_Darling
Start at the wiring diagrams. Your Haynes manual has B&W versions with labels for the colors. You can find full-color copies around on the web if you look.

Dig our your voltmeter and start checking for where you have voltage and where you have ground, and where you have neither.

--DD
930cabman
welcome.png

Was the car running when you purchased her?

Between Google and 914 World you will find a wealth of information.
rcautox
Regarding seat belt bypass-I pull the passenger seat, it looks like the bypass has already been addressed? Photo attached

Unfortunately it is FI, have to love 70s FI electrical gremlins….

I bought it and a 72 from the previous home owner. She lives next door so easy enough to ping her for info. The 74 ran fine until it just died one day. Her ex thought it was electrical. I’m starting with the simple stuff like battery and grounds.

From reading this site I suspect I need to move to the ignition next. I had a VW Vanagon with a 2.0 that also provided unreliable electrical services. I could bridge the starter with a screw driver with the key in the on position. Considered trying this on the 914 but I’m thinking fuel pump not running needs to be addressed?

Appreciate the help

Click to view attachment
Van B
So, two things to check:

1.) With the key on, push on the AFM flapper and see if the fuel pump kicks on.

2.) Now that you have confirmation of fuel flow, try to jump start the car across the starter terminals.

If the car starts, then we can narrow the scope of your starting issues.

IMPORTANT: Don't pedal the car when starting. Backfires break AFMs.
bdstone914
QUOTE(rcautox @ Feb 21 2023, 11:25 AM) *

Regarding seat belt bypass-I pull the passenger seat, it looks like the bypass has already been addressed? Photo attached

Unfortunately it is FI, have to love 70s FI electrical gremlins….

I bought it and a 72 from the previous home owner. She lives next door so easy enough to ping her for info. The 74 ran fine until it just died one day. Her ex thought it was electrical. I’m starting with the simple stuff like battery and grounds.

From reading this site I suspect I need to move to the ignition next. I had a VW Vanagon with a 2.0 that also provided unreliable electrical services. I could bridge the starter with a screw driver with the key in the on position. Considered trying this on the 914 but I’m thinking fuel pump not running needs to be addressed?

Appreciate the help

Click to view attachment

@rcautox
Yes the interlock relay is bypassed. Check to see if you have power in the yellow wire as is comes from the ignition switch and then out of that connector. If you do check the fuel pump fuse on the replay board. It is the fuse closest to the back of the car. rotate all the other fuses in the fuse panel They often corrode and loose contact.
wonkipop
QUOTE(rcautox @ Feb 21 2023, 11:25 AM) *

Regarding seat belt bypass-I pull the passenger seat, it looks like the bypass has already been addressed? Photo attached

Considered trying this on the 914 but I’m thinking fuel pump not running needs to be addressed?

Appreciate the help

Click to view attachment


on a stock 1.8 L Jet the fuel pump only runs when cranking.
then the AFM unit takes over running the pump once engine fires.
does not run with just the ignition on.

you can test by taking the air cleaner out and unclipping bottom.
leave the AFM plugged in.
with the bottom off you should be able to see in to where the AFM flap is.
with ignition on push the AFM flap carefully in.
you should hear the fuel pump run if its all ok.

ah i see @Van B has already instructed.

i'd check all the ground points are clean and corrosion free.

wiring diagrams can be found here.

http://p914-6info.net/Manuals.htm
rcautox
Thank you for the detailed suggestions. I gently pushed the AFM flap but no fuel pump. I moved to the yellow wire, no power or continuity. I figured I need to focus my efforts on the ignition switch and I found the relay was unplugged. I now have power to the gauges and the fuel pump kicks on when I push in the flapper.

If I’m reading the wiring diagrams correctly the yellow wire goes from my ignition switch to the starter. So next step I should think is the lack of continuity or power when the ignition is on? The starter does turn over if I jump the terminals.

The previous owner left a bunch of parts including a steering column so, along with the oddly unplugged ignition switch, I’m guessing they had identified this as a possible issue. Any advice on how to identify the source of the issue with the yellow wire?
StarBear
On 1.8s, don’t forget the unique dual relay and capacitor pack below the battery.
wonkipop
QUOTE(rcautox @ Feb 21 2023, 11:50 PM) *

Thank you for the detailed suggestions. I gently pushed the AFM flap but no fuel pump. I moved to the yellow wire, no power or continuity. I figured I need to focus my efforts on the ignition switch and I found the relay was unplugged. I now have power to the gauges and the fuel pump kicks on when I push in the flapper.

If I’m reading the wiring diagrams correctly the yellow wire goes from my ignition switch to the starter. So next step I should think is the lack of continuity or power when the ignition is on? The starter does turn over if I jump the terminals.

The previous owner left a bunch of parts including a steering column so, along with the oddly unplugged ignition switch, I’m guessing they had identified this as a possible issue. Any advice on how to identify the source of the issue with the yellow wire?


i'm hopeless at electrical stuff. so not much help.
but at least you got a fuel pump that is properly wired in.
where is your fuel pump located, still in stock position under engine bay on rhs?

having that fuel pump wired in right will help if there is further diagnosis required to get the L jet to run sweet again.

someones bound to pipe in with electrical advice who knows what they are talking about.

good luck with it. L jets forever. beerchug.gif



Van B
QUOTE(rcautox @ Feb 22 2023, 12:50 AM) *

Thank you for the detailed suggestions. I gently pushed the AFM flap but no fuel pump. I moved to the yellow wire, no power or continuity. I figured I need to focus my efforts on the ignition switch and I found the relay was unplugged. I now have power to the gauges and the fuel pump kicks on when I push in the flapper.

If I’m reading the wiring diagrams correctly the yellow wire goes from my ignition switch to the starter. So next step I should think is the lack of continuity or power when the ignition is on? The starter does turn over if I jump the terminals.

The previous owner left a bunch of parts including a steering column so, along with the oddly unplugged ignition switch, I’m guessing they had identified this as a possible issue. Any advice on how to identify the source of the issue with the yellow wire?


Good find on the relay. So, does it still not crank with the key?
rcautox
Fuel pump is in the front. I pulled the tank, cleaned it out and installed new lines from Tangerine Racing. I know location varies by year but the pump sure looks to be better in the stock location based on wiring and the little recess on the trunk wall.

No start with key. I should get some voltage on the yellow wire under the pax seat with key in the acc/on position? I ask because I’m seeing none. Thinking there may be a short in the wire between ignition and starter or the ignition switch is acting up (which could explain the spare parts and unplugged relay)
Dave_Darling
The yellow wire should be getting power only while the key is in the "starting" position. In "run" it should not, otherwise you'd have your starter engaged while driving the car, which is not what you want.

--DD
wonkipop
QUOTE(rcautox @ Feb 22 2023, 10:56 PM) *

Fuel pump is in the front. I pulled the tank, cleaned it out and installed new lines from Tangerine Racing. I know location varies by year but the pump sure looks to be better in the stock location based on wiring and the little recess on the trunk wall.



ah
it sounds like you actually have a model year 75 if it has the little recess in trunk wall and fuel pump there.

whats the VIN label on the door say for date of manufacture. will have month and year?

fairly similar to a 74 model year 1.8 but there are some differences with components.
might be relevant to getting it running once you sort out ignition electricals.
rcautox
In the starting position I do not have power in the yellow/red stripe wire, I do have power in the yellow wire. Looking at the wiring diagrams I think the yellow/red wire comes from the ignition switch. So either the current connection of the two yellow wires is bad or the ignition switch is bad?

You are correct-it is a 75. Checked the vin and engine # to confirm it’s a 75 with a 1.8l. Good catch for future fixes.
porschetub
QUOTE(rcautox @ Feb 26 2023, 09:53 AM) *

In the starting position I do not have power in the yellow/red stripe wire, I do have power in the yellow wire. Looking at the wiring diagrams I think the yellow/red wire comes from the ignition switch. So either the current connection of the two yellow wires is bad or the ignition switch is bad?

You are correct-it is a 75. Checked the vin and engine # to confirm it’s a 75 with a 1.8l. Good catch for future fixes.


could most likely be the crappy ignition switch ? when mine failed it went from occasional no crank to nothing @ all,some other functions still worked however.
Switch cover was cracked @ the spring .
Dave_Darling
QUOTE(rcautox @ Feb 25 2023, 12:53 PM) *

In the starting position I do not have power in the yellow/red stripe wire, I do have power in the yellow wire.


How would you have power in the yellow wire when it isn't in the yellow/red wire? It sounds like something is connected wrong, or we are talking about different wires than I think we are.

--DD
r_towle
You have power, key in start position, to the yellow wire in this picture and not to the yellow wire with red stripe, in this picture? At this specific location?
rcautox
I removed the male spade connector and tested each wire in the run position. The yellow/red stripe wire has no power, the yellow wire does at the location in the picture (under the pax seat).
Van B
Yeah don’t forget they are plugged like that because they both used to plug into the relay. So if you disconnect them you’re not gonna have power at all
Dave_Darling
The whole idea is that the yellow wire carries the power to the yellow/red wire. (Unless I've got those backwards.) If you unplug them, then one of them won't have power and that is completely expected.

When they are plugged together, do you get power at the other end of the yellow/red wire? That end is in the 14-pin connector on the front of the relay board in the engine bay. If you get it there, plug that connector back in and check on the 12-pin connector on the right side of the relay board. One of those pins gets a yellow wire as well; and with the front plugged in that should get powered when the key is in the "start" position.

If that gets power, then plug the 12-pin connector back in and check the other end of the yellow wire, which should be at the starter.

--DD
rcautox
Thank you for the help! I have power at pin 1 on the 14 pin connector and, with 14 pin connector plugged in, I have power at pin 6 (male end for the 12 pin connector) on the relay board. I plugged in the 12 pin connector back and found I do not have power at the yellow wire at the starter. I thought it is a straight shot from the yellow wire in the 12 pin connector to the starter? So I have a bad connection at the 12 pin connector or??
Dave_Darling
Sounds like either a bad connection there, or maybe the wire from the connector to the starter is bad.

--DD
rcautox
I pulled the cover off the 12 pit connector, gently pushed on the #6 pin to make sure it had a good connection-success! The starter is now engaging. Next-fuel and spark….

Thanks for helping track this issue.
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