Chrysler Moves to Fuel Injection and Turbochargers

Chrysler Moves to Fuel Injection and Turbochargers

The first use of electronic fuel injection was similar to modern EFI setups; it was created by Bendix and first installed on Chrysler cars. The system was a disaster, and it was quickly replaced by carburetors on nearly all the fuel injected cars; Bendix sold the patents to Bosch, which essentially waited for materials and computer technology to catch up.



One may ask why fuel injection was not used earlier in the 1980s; in the United States, for example, Volkswagen implemented multiple point injection on its mass-market Rabbits in 1979, with great success. Burton Bouwkamp wrote:

This is hindsight-and only my opinion. Our engineering effort on fuel injection was inadequate-it was at a "hobby" level rather than at a "development" level. The primary reasons were engineering budget problems (Chrysler was run by "bean counters" from 1962 through 1978); and we did not have a "champion" for fuel injection (a VP, an Engineering Director, or a Chief Engineer).

The 1958 and 1981-83 [Imperial] experiences certainly dampened whatever spark there was within the company for fuel injection. Bendix had a good mechanical system in production in Europe and we should have adapted that design to our engines. [Throttle body fuel injection was added to the 2.2 liter engine in 1984, the same year the multiple-port injected, turbocharged 2.2 liter engine debuted.]

As you know we kept leaning out and leaning out the carburetor to meet ever more stringent emission standards until the engine didn't run very well. It frequently took several engine restarts to back our 1985 cars out of the driveway in the morning.

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Backing up Burton Bouwkamp's opinion that fuel injection was treated as a hobby rather than being properly developed is Richard Samul's recollection of how it was done.

In the late 1970s, I worked on Chrysler's first attempt [since 1958] at electronic fuel metering. The project was started in a large tent, built at the north end of the Highland Park Engineering complex. ... Because this project was new technology, and deemed a possible fire hazard, initial testing took place outdoors.

The 1981-83 Chrysler Imperial used the electronic fuel metering system. This system was prone to magnetic fields generated by power lines along roadways. This caused the fuel system to go rich at partial throttle and affected drivability.

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The Imperial, Chrysler's first modern car with fuel injection, had a troublesome system, but it may have worked well with more testing up front. Marcos wrote:

A low pressure electric pump in the tank supplied fuel to a high pressure control pump. The speed of the control pump determined the quantity of fuel injected and was controlled by the computer by varying the voltage.

Fuel was injected by a spray bar assembly. The regulator had two tubes coming out of it on each side, which jutted out over the throttle openings, and each bar had two fuel openings over each throttle plate (for a total of eight). There was a "low-speed" spray bar which worked up to about 30psi, and the fuel openings had brass nozzles for a fine spray. Above 30psi, the regulator opened to send fuel to the "high-speed" fuel bar. The openings were just pinholes, and delivered fuel in a stream, but the velocity of the air going through was supposed to provide enough atomization.

In principle, it was a simple system. A mass air sensor found the quantity of air being ingested. The computer drove the pump and an optical flow meter on the outlet provided a feedback signal to control the air-fuel ratio. The oxygen sensor provided further feedback for fine tuning, and a way to calibrate open loop modes. Temperature sensors for the air and fuel provided further information for adjustment, and the distributor pickup and throttle position sensors triggered certain modes (e.g. idle, full throttle). The computer calculated manifold pressure, because there was no sensor.

This system was plagued by electrical issues, mainly due to the somewhat primitive design and crude components. The biggest complaints were stalling or no-start. The auto shutdown relay was prone to being tripped by electrical noise. Due to being mass-air-sensed through the air cleaner snorkel, it was very sensitive to vacuum leaks. Corroded connectors and grounds caused lots of issues over the years.

When they run, they run very well, much better and smoother than the 2bbl 318s of the time. They incorporated several physical features around the throttle butterflies and throats to improve fuel atomization. These cars were capable of pretty decent fuel economy.

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The system was not used for later cars. Instead, Chrysler dropped the mass air sensor and set up a different system for its 2.2 and 2.5 liter engines.

Trouble with past injection systems was not the only reason why Chrysler kept carburetors beyond the point where they could be reasonably well tuned; after all, the 1979 Volkswagen Rabbit had a perfectly reliable multiple-port injection system (which, oddly, did not have relatively cheap and simple electronic ignition). Engine development leader Pete Hagenbuch said that the issue was cost - a carburetor cost around $20, while an injection system cost around $100. Fuel injection required more sensors and higher fuel pressures, as well as the costly injector itself.



The cost issue worked both ways, though. Chrysler cost estimator Warren Steele wrote, "EFI replacing carburetors was fun. That was a long and complicated adventure. Because idle speed, fuel air mixture adjustments were built into the computer, we no longer required manual adjusting which dealers were back-charging to us-a big cost saving. After a year of getting charged for adjustments no longer possible, we convinced dealers about non-existent adjustments."

Starting in 1984, though, carburetors would be systematically replaced by a reliable, well-developed, albeit relatively inexpensive fuel injection system. As Burton Bouwkamp wrote:

The throttle-body (TBI) EFI [used by Chrysler on all non-turbocharged engines in early years] was certainly not anywhere close to port injection, but it gave a better control of the air-fuel ratio than did the trusty old carburetor. In fact, the principal reason we all wanted to get rid of TBI was the number of calibrations which would not have been needed with MP [multiple port] EFI. It was always a cost vs. quality argument and I imagine the decision was made at a much higher level.

If there had been an airflow meter available then which gave accurate and repeatable measurements, we might have been able to sell it to management. With TBI, fuel-air distribution was essentially the same as a carburetor, and a new calibration was needed for every engine-car combination.

... everybody hated throttle body injection, well there were a lot of reasons for that, one was that we were left with the same problem we always had and that was trying to get half way decent mixture distribution to all of the cylinders. A single throttle body was no more help than an antique carburetor.

The thing that always bothered us about our system, for probably the first 20 years every single fuel injection system that we released was based on RPM and charge density, not an air flow meter. Air flow meters were expensive. But you could calibrate a whole family of engines with one air flow meter. Those that I worked for were sure that it was cheaper to do a thousand calibrations on TBIs.

Everybody hated it, it was stupid, and it was ridiculous. There had to be a different set of electronics between an A body and a P body of the same engine. There had to be different electronics for every insignificant variation of every engine model, and each had to have its own calibration which took weeks and several people, one engineer and a couple technicians and a dyno operator not to mention car work for drivability. We did it over and over and over, it was just plain stupidity. It was also a lousy way to build fuel injections because what you were doing was you were calculating air flow from the density and the RPM, density being manifold vacuum or pressure in the case of a turbo.

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Turbochargers were used to bring Chrysler's ubiquitous four-cylinders up to V6 power, cutting the need for Mitsubishi imports and allowing more power in smaller cars. Pete wrote:

Working with the turbo was fun but I would have preferred to do a Rootes Type supercharger. I argued the point as far up as I felt comfortable but TURBO was a magical word at that time at Chrysler. Ford (GT) and GM have both proven me right but that don't help much. We had a unit, from Eaton, but I couldn't even get permission to do a quick 'n' dirty job with it.

... They wanted turbocharging, it was the thing of the moment. It was far superior if you were going for maximum, top end output. Who the hell wants maximum, top end output on a passenger car?

Supercharged cars blow your mind up to 60MPH. There are ways to reduce all the friction they absorb when you're at part throttle, you can dead head them, you can bypass them, and you can do all kinds of things. They can be built to get reasonable fuel economy.

... I was the guy responsible for the performance of the 2.2 and later 2.5 turbos. We had no one in-house who knew much more than the very basics. It was pretty much learn as you go. The electronics folks at Chrysler were not any better off. Engine designers had one thing right; mount the turbocharger as close as possible to the exhaust manifold to reduce heat losses.

We learned a lot about turbocharging and, yes, the 2.2 responded to everything we did.

The men behind the 2.2 Turbo:
Willem Weertman | Pete Hagenbuch
Marc Rozman

Our biggest difficulties lay with detonation, or the detonation sensor which was, I think, unreliable. Given this, the specified fuel could not be regular octane. I fought this battle and eventually won something in the owners' manual saying better performance and longer life could result from the use of high octane fuels. This was a big breakthrough. I had several different turbo lease cars and they were fine; they never tasted low octane fuel.

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