Glow plug wiring: Not getting enough amps to starter solenoid

[Grubby]

THis is regarding my 240 d24t engine swap. I just started it yesterday for the first time and it is running nicely. However, in order to start it we (me and Wren) had to bypass the stock ign. switch wire with a jumper from the battery to solenoid. According to my green book diagram, I had wired the solenoid wire directly with the wire that inputs to the GP relay. so that it gets the starter signal to cycle the plugs during starting. I tapped into the wire before it reached the solenoid.

This morning, when I checked voltage at the solenoid wire, and it was around 10 volts with the GP relay wire connected. When I disconnected the GP relay wire, the voltage was back up to 12.10 or something. So, it seems that the ign. switch is working, but the relay is drawing enough on the circuit that it is reducing the voltage at the solenoid, and the solenoid won't engage. All the lights dim when I try and start it, which tells me some significant current is being drawn, but the solenoid is not even clicking. DOn't think wiring the GP relay wire directly to the solenoid would help, but who knows? IN fact, when I put my multimeter on all the wires where I had them pigtailed, I got that same low voltage. Does anyone have any ideas about this? I have a new GP relay, maybe I'll try that one and see if it draws less.
Thanks for any help, and Happy Easter to those who celebrate it!
Abe

[Grubby]

I figured it out: when the GP wire is in the starter circuit, it is cycling the glow plugs when starter motor is engaged, which is too much for my little battery from my gasser. I just need the right sized battery. Never mind.

[v8volvo]

Sorry for no replies, I (and I suspect others as well) spent some time pondering this and couldn't come up with much... glad you were able to sort it out.

A bigger battery is always good and quite necessary for starting a diesel engine, but if, with the smaller/weaker battery, you could still start the car by hard-wiring the battery to the solenoid, it sounds like you still have excessive resistance in your starter signal circuit. Ignition switch may have poor contact, or if you converted the car from automatic and the PNP switch jumper connection is not good, you can lose some volts there too. Putting in a stronger, higher-capacity battery will probably be enough to make it work OK, but in a sense it is a patch masking an underlying problem that may cause more problems for you further down the road. If you have excessive voltage drop in that circuit, it won't take much drawing down of the battery before the car becomes hard/impossible to start. May be worth further investigation still if this is a car you plan to depend on for reliable transportation.

Sometimes too, however, the starter solenoids can get weak and won't engage unless they see more volts than should be necessary. Member ngoma and I had a run-around last year with a couple Bosch model SR97 starters that were plagued by this issue. Both tested fine and ran strongly on the bench, but when installed into a car, one of them would not ever engage at all, while the other sometimes worked OK but often would fail to engage or would half-engage and crunch the ring gear teeth. And, both were brand new Bosch OE reman units! After the second bum unit, I got fed up and took it to a good local rebuilder, who rebuilt my shiny new starter with another new solenoid. It has worked fine ever since. The rebuilder said that some crappy or aged solenoids become overly sensitive to the normal small voltage drop that happens in the ignition switch and wiring, so what seems like a wiring issue may just be a tired solenoid. And, hate to say it, but pulling/rebuilding/installing a starter is still easier than replacing an ignition switch! By my reckoning, anyway...

In any case, I doubt if the current is being drawn by the GP relay, since it and/or its little wires would certainly burn up if they were taking enough juice to dim the lights that much. However, even with a discharged battery, you should be able to crank the starter with the key any time that you can crank it with a jumper to the battery. So if this were my car, maybe not immediately but in the long term, I'd probably want to look further whatever issue is causing that difference.

Congrats on getting it running! That is the big step... now the rest is little stuff. Much easier to find the motivation to finish tying up the loose ends and get it on the road after you've heard it light off in its new home. :cool:

[RedArrow]

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50Good thinking.

Let me share with you how my ignition switch went kR/\zY … & how it came back to life.
First of all, let`s start with the lesson itself: When detailing your car, it`s highly suggested to be cheap with the liquid interior cleaners around your Volvo`s ignition switch area. Ask me how I learned not to use too much `ArmorAll`! After a few weeks of intermittent electric gremlins, after many angry words; finally, in the middle of my Florida vacation (in a nasty and dark bsmt parking lot of a motel in Daytona Beach), my ignition switch`s stupid games reached the highest and I got stuck right there. That time I did not know what was going on. The car did not want to start, I mean, my ignition switch did not work anymore and my dash lights did not come up at all, except for the sealtbelt warning light. It had happened before but a wiggle-jiggle with the key always helped. No more. `OK`, let`s see all fuses, check wires & do your best. I still couldn`t figure out why the car was playing this not-so-funny game. I inspected & cleaned all connections I could find but no luck. The car was warm, cranked strongly but did not want to start, of course… I checked/reconnected battery terminals, glowplug relay, fuses, wires, even removed and cleaned all ground locations on&around the engine. The car is very reliable and drove thousands of miles without ANY issues… Only some minor electric problem I suspected but could not find it and gave up. I decided to hotwire the car somehow… Luckily my best Volvo-friend, George, found the solution… after he looked at the wiring diagram he helped me out through the phone. The electric part of the ignition switch had to be removed and new connections fabricated to start the car like I was stealing it. I had extra wires with me, a Voltmeter & all tools, luckily. I was told to cut many pieces of 8-10inch long wires and follow his instructions to connect them in a special way&order (long story!)One wire was left hanging there, that was used to start the car and then it must be disconnected. Just like in the movies. And the car did start! What a happy moment! I was very glad to hear it running again after so many hours of brainstorming. From now on, the key was only used to not let the steering wheel lock itself when driving. The car had to be started by a piece of wire for many days.
I visited the Volvo stealership to buy a new ign switch but I was told that it would take 2-3days and $157 to get the switch. What?! (IPD $111)
I took the ignition switch apart and was horrified to see the inside of it. Some oily, sticky, honey-like residue covering it all. I had the full heat on for days so I cooked that thing. I had to completely take it apart and soak all its little parts in grease remover (except for the plastic part). When thoroughly cleaned and dried, I used some lubricant on the spring and put everything back together, installed it in the car and since then it has been working fine. I do remember by now that in Yellowstone NP, the multiple-day snowstorm froze all my locks (and fingers ) and it was hard to get in the car so I used WD40 in the rear gate lock and also on the passenger side door. Some WD40 surely got into the ignition switch as well (from the key). Also some of the spray-type dashboard-cleaner, I guess. It was a painful but effective lesson. I will keep the ready-made wire-junction as a reminder/souvenir from FL. Take it easy with cleaning supplies! 

[verdigo]

I had the same problem with low current at the starter solenoid. I mounted an old Ford firewall mounted starter solenoid with 10 ga wire straight to the battery. When I hit the key now it sounds like someone is hitting the firewall with a hammer.

Dennis